Swedish intervention in the Thirty Years' War facts for kids

Quick facts for kids Swedish Intervention
Part of the Thirty Years' War
Gustavus Adolphus at the Battle of Breitenfeld
Date 1630–1635 Location Throughout the Holy Roman Empire Result Peace of Prague Most of Sweden's German allies making peace with the Emperor End of the civil war phase of the Thirty Years' War Direct French intervention against the Emperor and Spain
Belligerents
Swedish Empire  Saxony (from 1631) Heilbronn League (from 1633) Hesse-Kassel Brandenburg-Prussia Support:  France	Catholic League and allies:  Habsburg Monarchy Spanish Empire
Commanders and leaders
Gustav II Adolf  † Axel Oxenstierna Johan Banér Lennart Torstenson Gustav Horn Bernard of Saxe-Weimar Alexander Leslie John George I George William William V of Hesse-Kassel	Albrecht von Wallenstein  † Count Tilly  † Ferdinand II Ferdinand III Gottfried Pappenheim  † Maximilian I of Bavaria
Strength
1630: 70,600 13,000 men landing in Germany 10,000 infantry 3,000 cavalry 24,600 men garrisoning Sweden 33,000 German allies and mercenaries 1632: 140,000 25,000 Swedes and Finns in Germany ~115,000 German allies and mercenaries	1632: 110,000 pro-Imperial troops in Germany
Casualties and losses
86,300 killed, captured and deserted	80,760 killed, captured and deserted

The Swedish Intervention was a major part of the Thirty Years' War, a huge conflict that swept across Europe. It happened between 1630 and 1635. Before Sweden joined, the Protestant side in the war was almost defeated. But when the Swedish army arrived, they won important battles and completely changed the war's direction. The Catholic forces, who had been winning, became much weaker because of Sweden's actions. Some historians even see this period as a separate conflict within the larger Thirty Years' War.

In 1629, the Holy Roman Emperor Ferdinand II issued the Edict of Restitution. This order threatened to take away lands from Protestants, making their situation very difficult. So, in July 1630, King Gustav II Adolf of Sweden landed in Germany to help the German Protestants. Even though King Gustav II Adolf was killed in battle at Lützen in 1632, the Swedish armies kept winning against their Catholic enemies. However, a big defeat at Nördlingen in 1634 made it hard for Sweden to continue fighting. After this, the Emperor made peace with most of his German opponents through the Peace of Prague. This peace basically canceled the Edict of Restitution. At the same time, France directly joined the war against the Emperor and Spain to stop the Habsburg family from becoming too powerful.

Sweden continued fighting until the Peace of Westphalia in 1648. In this peace treaty, the Emperor had to accept that German states could have more freedom. Sweden also gained control of Western Pomerania.

Why the War Started: The Bohemian Revolt

Emperor Charles V tried to stop the spread of Protestantism. He couldn't force Lutherans to return to the Catholic faith, so he had to agree that each prince in the Holy Roman Empire could choose the religion for their own land.

The Thirty Years' War was a religious fight between Protestants and Catholics in Germany. It grew out of the mix of politics and religion common in Europe back then. Its roots go back to the previous century, to an agreement called the Peace of Augsburg. This peace treaty, signed in the 1500s, made Lutheranism a legal religion in Germany. It allowed local rulers to decide the religion of their area. This was known as Cuius regio, eius religio (meaning "whose realm, his religion"). People who didn't agree with their ruler's religion could move to another area where their faith was accepted.

Sometimes, rules of the Peace of Augsburg were broken. For example, if a church leader who ruled land became Protestant, they were supposed to give up their land. This didn't always happen. Even with these problems, a big war didn't break out right away. The Peace of Augsburg was only a temporary stop to the fighting. It was hoped that one day, Protestants and Catholics would reunite, but this seemed unlikely unless Protestants were forced to change.

Many German princes became Protestant not just for religious reasons, but also to gain wealth and land from the Catholic Church. They could take valuable church property for themselves.

Protestants knew they needed to unite against the Catholic Church to protect themselves. However, they were divided. Lutherans and Calvinists had different beliefs. The Catholic Church tried to keep these Protestant groups fighting among themselves. Because of this, German Protestant states couldn't work together against Catholic power.

Both sides often accused the other of breaking the Peace of Augsburg. Protestants believed Catholic officials wanted to harm their cause. Catholics thought Protestants were greedy for church property. This strong dislike between Protestants and Catholics in Germany meant that misunderstandings were common.

The Holy Roman Empire in 1618, just before the war began.
Habsburg-controlled areas are shown in yellow.

The Thirty Years' War really started with a local argument in Bohemia (part of today's Czech Republic). Bohemian Protestants were unhappy with their Habsburg rulers. Emperor Rudolf II, Holy Roman Emperor had to give up some of his lands to his brother, Matthias, because of problems with the Ottoman Empire. Seeing this weakness, the Bohemians revolted. In 1609, Rudolf gave them more religious freedom. But when they asked for even more, Rudolf sent an army. Matthias then took over from Rudolf, becoming the Holy Roman Emperor in 1611.

Matthias had no children, so in 1617 he chose his cousin, Ferdinand of Styria, to be the next King of Bohemia and his successor. Ferdinand was a very strong Catholic and didn't like to compromise. When he became King of Bohemia, he reversed some of the religious freedoms Matthias had allowed. When the Bohemian leaders protested, he closed their assembly.

The immediate spark for the Thirty Years' War was the Third Defenestration of Prague in May 1618. Protestant noblemen stormed Prague Castle. They grabbed two imperial governors and threw them out of a third-floor window! Luckily, the officials landed in a pile of manure and survived.

Both sides immediately looked for allies. The Bohemians were in a tough spot against a powerful emperor with many strong allies. They asked for help from different European leaders. They also tried to join the Protestant Union, a group of German Protestant states. When the Elector of Saxony refused to be their king, Frederick V, a Calvinist, became their choice. He was married to Elizabeth Stuart, the daughter of the King of England, so the Bohemians hoped for English help.

However, choosing Frederick as king against Ferdinand, the rightful ruler, made other German and European powers hesitant. Many warned Frederick not to accept the crown. But he did.

Sweden's Situation Before the War

King Gustavus Adolphus of Sweden knew about the war in Germany, but he was busy with problems with Poland. The Polish royal family, the House of Vasa, believed they had a right to the Swedish throne. This was because Sigismund III Vasa had once been King of Sweden. But when he became King of Poland, he had to be Catholic. Sweden, however, was mostly Lutheran.

A map showing Europe when Sweden joined the Thirty Years' War and the path of Sweden's campaign.

One reason Sweden became Lutheran was that it allowed the king to take all the lands owned by the Catholic Church. This made the Swedish crown much more powerful. Sigismund's support for the Catholic Counter-Reformation also caused problems in Sweden. After a defeat in battle, the Swedish nobles demanded Sigismund rule from Sweden. But he returned to Poland and was removed from the Swedish throne in 1599.

Gustavus Adolphus's uncle, Charles IX, became king. He was a strong Lutheran. Sweden then got into wars with Denmark-Norway and Russia. Sigismund III of Poland never gave up his claim to the Swedish throne, so Poland often tried to get it back. Sweden was fighting on many fronts.

Charles IX died in 1611. Gustavus, only 17, became king. Many thought he was too young to handle the wars. But Gustavus had been training in the army since age 11 and knew how to govern. He surprised everyone.

He quickly ended the wars he inherited. By 1613, he forced the Danes out. By 1617, he made Russia give up territory to Sweden. Gustavus also made truces with Poland, which gave him time to deal with other enemies. He tried to make a lasting peace with Poland, but Sigismund always refused.

Newspapers showing Sweden capturing many cities.

Sweden's Military Changes

The time of peace with Poland helped Sweden a lot. Gustavus used it to create a military system that became famous across Europe. He wrote new rules for the army. These changes also helped Sweden's economy. The military reforms, especially strict discipline, made the Swedish army one of the best.

The new rules encouraged soldiers to live simply. No silver or gold was allowed in the army camps, not even in the King's tent. Soldiers caught stealing were shot. Favoritism was not allowed. The system for supplying the army was also made very efficient. Soldiers and officers had to carry less baggage to move faster. Everyone had to do garrison duty, no exceptions.

Other changes included having a chaplain for every regiment. Prayers were said before every battle. It was unusual to see high-ranking generals kneeling in prayer next to ordinary soldiers in Germany. Crimes like theft, disobedience, and cowardice were judged by a military court. The king made the final decision. Military police were given power to execute soldiers on the spot if they disobeyed orders. All trials for serious crimes were held outside, in front of other soldiers.

If a regiment committed crimes, like running away from battle, one out of ten soldiers might be chosen by lot and executed (this was called decimation). The rest of the regiment would then be given unpleasant tasks. Violence against women was punished with death. Duels were forbidden. Once, when two men asked to duel, the king attended and told them to fight to the death, adding that he had an officer ready to execute the survivor.

While many Swedish soldiers came from noble families, Gustavus also created a new nobility based on merit. Soldiers who showed courage and did well in battle were paid well and given pensions. This new nobility helped the king gain support against the older, independent noble families. Sweden became a strong military monarchy.

The Swedish army's engineers were the most advanced of their time. People in Germany were surprised by how well the Swedes built trenches and used their equipment. The army also had a special group of miners, and all soldiers were trained in building defenses and pontoon bridges. This was also when the first general staff was created.

Many changes were also made to the government to improve cooperation. A system called the "House of Nobles" was created to organize society better. It included nobles, clergy, townspeople, and peasants. Nobles could not represent more than one group to prevent too much power in one place. Peers had to attend meetings but were expected to listen silently. Even with new nobles, the traditional nobility had more ways to influence the government during Gustavus's reign. However, the king still held most of the power.

The government avoided simony (selling church positions), which helped the state financially. With these military and government improvements, Sweden was ready to end its wars with Poland and succeed in Germany.

Ending the Polish Wars

The Swedish royal family had long claimed lands in Swedish Livonia. Using this as an excuse, Sweden invaded Polish-held territories. Sigismund of Poland was still determined to regain the Swedish throne. He had support from powerful Catholic rulers like the Habsburg kings of Spain and the Holy Roman Emperor Ferdinand II, who were also related to him by marriage. Spain even declared that Swedish ships in Spanish ports could be legally seized. Sweden was Protestant and allied with the Dutch Republic, which was fighting Spain. This made a lasting peace difficult.

So, war broke out again between Sweden and Poland in 1621. The Swedes landed near Riga with 158 ships and besieged the city. Riga's people weren't loyal to Poland because they weren't Catholic. Also, Sigismund was busy fighting the Ottoman Empire in the south and couldn't help Riga. After four weeks, the city surrendered.

Frederick V, who was King of Bohemia for a short time and leader of the Protestant Union. He was the King of England's son-in-law. His decision to accept the Bohemian crown against Ferdinand II started the Bohemian Revolt.

Gustavus then marched into Poland. Sigismund, unable to fight on two fronts, offered another truce. Gustavus couldn't get a permanent peace, but Sigismund agreed to a truce and let Sweden keep the part of Livonia they had captured. Gustavus returned to Stockholm in late 1621.

Gustavus had no heir at this time, and his brother, the next in line, died in early 1622. Sigismund saw this as a chance to claim the Swedish throne. He wanted to build a fleet and eyed Danzig, a major trading city in the Baltic. Emperor Ferdinand II, who was Sigismund's brother-in-law, encouraged this. Gustavus, seeing the danger, sailed to Danzig in June and forced the city to stay neutral. With Danzig neutral, Sigismund proposed extending the truce, which was agreed upon for the next three years.

Ferdinand II, Holy Roman Emperor from 1619 to 1637. He inherited the Thirty Years' War and had more resources in Germany than any other prince.

During this peace (until 1625), the king continued to improve Sweden's military. He planned for a regular army of 80,000 men, plus a large National Guard.

Other Protestant powers like England and the Dutch Republic had been giving some help to the Protestants in Germany. Both Sweden and Denmark wanted more aid to join the German conflict. Gustavus had specific demands, but Christian of Denmark offered a lower price, so he received the support. However, the Danes were defeated at the Battle of Lutter by the Catholic League under General Albrecht von Wallenstein. This led to the Treaty of Lubeck, which removed any major Protestant fighter from Germany. The Holy Roman Emperor effectively controlled all of Germany.

Ferdinand, feeling confident, issued the Edict of Restitution. This order aimed to return lands that had been taken from the Catholic Church back to Catholic control. This included important areas like the Archbishopric of Bremen and the city of Magdeburg, along with many other church properties. The edict also allowed forced conversion of Protestants to Catholicism, which directly broke the Peace of Augsburg.

Gustavus didn't want to land in Germany until he had secured Sweden. He finally decided to end the problems with Poland. In 1625, he sailed to Livonia again. Danzig had allowed Polish forces to guard it, so Gustavus immediately marched his army there and besieged it. The king was wounded twice during this campaign, once very seriously, so he couldn't lead the army in person. This caused some setbacks, but Sweden's position wasn't seriously damaged.

Finally, the king ended the conflict with Poland. In 1628, he sailed through Danish waters (after a treaty allowed it) and landed again. The Emperor sent forces to help the Poles, but the Swedes pushed them back and reached a final agreement with Poland. Sigismund agreed to a five-year truce.

Getting Ready for Germany

Gustav II Adolf, King of Sweden (1611–1632), also known as "The Snow King." He made Sweden a major European power and is considered one of the greatest military commanders ever.

Gustav Horn, a skilled military leader trained by Maurice of Orange. He became a field marshal at 35 and was one of King Gustavus Adolphus's main commanders during the invasion of Germany.

Even though Protestants had some early wins, the Emperor controlled most of Germany. The Protestant and anti-Habsburg allies weren't working together well. France promised money to Denmark but didn't always deliver. The Dutch Republic, while supporting Protestants, didn't want Sweden to control the entire Baltic coast for economic reasons.

Johan Skytte, a baron and governor, was a close advisor to Gustavus's father and tutored the king. He was a key political figure and diplomat during Gustavus's reign.]] Bogislaw XIV, Duke of Pomerania, promised help, but he was isolated. The Margraviate of Baden and William of Hesse also pledged support. However, once the Swedes were in Germany, these allies were often unwilling to contribute their resources. Only the dukes of Hesse-Kassel and Brunswick-Lüneburg were truly eager to join Sweden.

Despite the difficult situation for Protestants, there was unrest across Germany because of the terrible actions of the Catholic armies, which affected both Catholic and Protestant states. Everyone in Germany, and even France (who feared the powerful Habsburgs), worried about Emperor Ferdinand II's growing power. France supported Sweden's intervention but, being Catholic, only offered money, not open support. However, France refused Gustavus's demands for a large upfront payment and yearly contributions.

Sweden didn't have all the qualities of a great power, but it had the best military and the most efficient government in Europe. Still, Sweden's yearly income was only about 12 million rix dollars. This improved over time as the king increased taxes and took back control of valuable lands.

To raise more money, the king decided not to pay back old debts from before 1598. New loans were taken from the Dutch Republic at 6.5% interest and from within Sweden at 10%. The government had to offer its lands as security for these loans. The government also created monopolies on certain goods like salt, copper, and grain to earn more money. Overall, taxes were high and sometimes caused problems within Sweden.

Another challenge was Sweden's small population of only 1.5 million people. As the campaign in Germany continued, the king relied more and more on German mercenaries. These mercenaries were known for bad behavior, but under the Swedish military system, they were trained to be disciplined.

Axel Oxenstierna, a successful Swedish diplomat, soldier, and Lord Chancellor of Sweden throughout Gustavus's reign. He was a key figure in Swedish politics and led the Swedish state after Gustavus's death.

The king called a meeting of the most important men in Sweden. He convinced them that Sweden should join the war in Germany. He believed that once Ferdinand had finished in Germany, Sweden would be next. There were several reasons for Sweden to intervene. The Habsburgs had helped Poland against Sweden, even though Sweden and the Habsburgs were officially at peace. Also, at a meeting in Lübeck to discuss the war, Swedish representatives were rudely dismissed by Wallenstein's orders and even threatened with violence. This angered the king greatly. Finally, the king and the Swedish people felt deep concern for the oppressed Protestants in Germany. One historian said Gustavus was "flattered by the glory he hoped to gain as Protector of the oppressed, and passionately loved war as the element of his genius."

Stralsund, a Hanseatic city, was under attack by Imperial forces. Gustavus knew that if the Catholics took this area, the Holy Roman Emperor could invade Sweden. He had to act. The Emperor had 170,000 troops in Germany, and the small Protestant holdouts couldn't stop them alone.

So, preparations were made between 1629 and 1630. Large amounts of gunpowder ingredients (nitrate and sulfur) were collected. Factories making swords, armor, and other weapons worked at full speed. A war tax was put in place, specifically for nobles, to ensure everyone contributed. In the first year, three-quarters of the state's income went to the war effort. Churches were told to preach in favor of the war and conscription. All men aged 16 to 60 were called to serve. Families only had to send a soldier if they had at least one son. Nobles had to serve in the cavalry. Soldiers were also recruited from other countries, including Scots and Danes. Ambitious mercenaries joined the Swedish army as the king's military skill became known. Hanseatic towns also sent troops.

Sweden also had troops already in eastern Germany. Six thousand men were on the island of Rügen and in Stralsund, led by Leslie, a proven general. Leslie had also recruited from the Hanseatic towns. Another 12,000 men were in occupied Prussia and Livonia, under Axel Oxenstierna, the king's trusted first minister. By the end of the year, these forces grew to 21,000. To protect Sweden itself, 16,000 men stayed there. Another 6,500 were in Finland and the east, and 5,000 in the Baltic provinces. Gustavus believed he had to control the entire Baltic coast to protect his supply lines and throne. In total, 76,000 men were in Swedish service. Of these, 13,000 were meant for the first landing in Germany. These were later joined by 2,500 men from Sweden and 2,800 from Finland. The army included 43,000 Swedes, with the rest from other nations. About 3% of Sweden's total population was involved in the campaign, a heavy burden.

The cost to Sweden was over 800,000 rix dollars per year. The king hoped for significant contributions from his Protestant allies in Germany. With only 13,000 men for the landing, the king faced two Imperial armies (under Wallenstein and Tilly) that he thought had 100,000 men each. The king was taking a big risk, counting on recruiting more men in Germany. But his troops were highly skilled. He believed that once he won battles and captured important places, Protestants would gain confidence and join him.

Landing in Germany: Wollin and Usedom

The area where the war was fought.

The king didn't formally declare war. After the attack on his ally Stralsund, he felt he had enough reason to land without a declaration. He tried to negotiate with the Emperor, but neither side was serious.

The capital of Pomerania, Stettin, was under threat from the Emperor's forces. The king decided it was vital to land there immediately. He planned to land in May 1630, but bad winds delayed the fleet for three weeks. Two hundred transport ships and 36 warships were used for the landing. The king planned to land at the Oder river delta, secure the nearby cities, and then march up the Oder into Germany.

Gustavus Adolphus landing in Pomerania, near Peenemünde, in 1630.

The king studied the area carefully. Bogislaw XIV, Duke of Pomerania, was Protestant but was also negotiating with Ferdinand to protect his duchy. When he heard Gustavus was landing in his duchy, he asked the king not to make war there. The king told Bogislaw that he would land, and how his duchy was treated would depend on Bogislaw's actions.

Three days of public fasting and prayer were declared for the landing's success. The king made final arrangements for his government, ensuring his three-year-old daughter, Christina, would be his successor if he died.

Rivers and duchies of the Oder–Elbe region.

The landing happened on July 4 near Peenemünde on the island of Usedom. The king immediately captured and garrisoned important towns on the island. Upon landing, the king slipped and fell, but it was ignored. The first thing he did was kneel and pray. Then, he picked up a shovel and started digging trenches to protect the landing. It took two days for all forces to land, and as companies arrived, they immediately started digging.

Germany with key cities for the campaign.

Because the landing took so long, much of the army's food supplies were used up. The king, angered by this, lectured Johan Skytte, who was in charge of supplies. He ordered Oxenstierna to send supplies quickly from Prussia. Feeling secure, the king sent a small part of his fleet to Oxenstierna to gather more supplies.

After two days, the king took 1,200 musketeers and cavalry to the area opposite Wolgast (a town on the mainland). He saw an Imperial fortress there, studied its weaknesses, and ordered 4,000 more musketeers to join him. When they arrived, he moved towards the fortress, but the Imperials had abandoned it and moved to Wolgast. He left 1,000 men at the fortress and, with the rest (3,500 foot soldiers and 2,500 cavalry), cleared Usedom of Imperial forces. Imperials retreated to bases on Wolin, an island opposite Usedom. The king ordered his forces to garrison these bases and pursued the Imperials across Wolin. The Imperials burned the bridge connecting Wolin to the mainland to escape. The king had secured both Wolin and Usedom, controlling all the mouths of the Oder River into the Baltic Sea, and returned to his headquarters.

Securing Pomerania

The Duchy of Pomerania before Sweden took control in 1637.

Stettin was the capital of Pomerania, chosen for its central location. The Oder River divided the duchy. Stettin had been under siege by Imperial forces for some time, but they hadn't made much progress. Bogislaw still held the city. When Imperial generals learned of Gustavus's landing, they retreated. Savelli went to Anklam, and Conti went to Gartz and Greifenhagen (holding both sides of the Oder). Gustavus left Colonel Leslie in charge of Wollin and General Kagg on Usedom, both under General Knyphausen. He made sure these islands were safe from Imperial landings.

The king brought in 5,000 soldiers from Stralsund and gathered the rest of his forces, totaling 74 companies. By July 18, he had assembled this force and the next day set out from the Swine Inlet to Stettin. He was positioned between Savelli and Conti. If he took Stettin, he would have a key advantage by being on "interior lines."

Imperial army positions. Stettin was between the two cities the Catholic forces had retreated to. Taking it would give the Swedes a big advantage.

This meant he could move his troops to any point faster than the Imperials, reinforcing threatened positions or attacking enemy lines more quickly. This was especially important because his force was smaller than the Imperials'. He could move his troops between his lines as needed.

Despite his city being attacked, Bogislaw wanted to stay neutral. Colonel Damitz, defending Stettin, was ordered not to let Swedes in and to attack them if necessary. The king refused to speak to a low-ranking messenger, insisting on speaking only with Damitz. Some talks happened, but Damitz couldn't let troops in. The king and duke quickly met. The king told the duke he wouldn't allow neutrality and was ready to take the city by force, demanding immediate entry.

On July 20, after convincing Bogislaw (without a single Swedish casualty), the Swedes marched into Stettin. A treaty was signed, effectively making Pomerania part of Sweden's control. The king received money from the duke and replaced Damitz's troops with three of his own companies to guard the city. Bogislaw sent a message to the Emperor, but the Emperor declared all of Pomerania in revolt, allowing even more looting.

Swedish and Imperial territories after Sweden captured Stettin.

Soon after, the king received more troops from Prussia. Conditions in Germany were so bad that many men joined the Swedish army voluntarily; it was easier to get food in the army than in the countryside. With their new gains, the Swedes now had 25,000 soldiers. While many Germans supported the Swedes, there was also strong opposition. Several attempts were made to assassinate the king by Catholic supporters.

The king then ordered Stettin's defenses improved. All citizens and villagers were gathered to quickly complete the defensive works.

Despite their good position, the Swedes were still vulnerable. An Imperial force at Wolgast was preparing to attack Usedom. Imperial camps were also at Garz and Griegenhagen. They still held Damm, opposite Stettin, which meant Stettin wasn't fully secure. On July 22, the king ordered a unit to capture Damm. After taking it, the king ordered Damitz to take Stargard. This city was taken, and soon after, Treptow and Greifenberg were also captured. Other cities were taken to prevent the Imperial force at Kolberg from joining their comrades. The king carefully guarded these cities. The king's next target was Garz. Once, while scouting, an Imperial patrol captured him and his guards. Not knowing who he was, they weren't careful, and his main guard quickly rescued him. The king was so reckless about his safety that this happened twice.

The area where the campaign was happening, including Ueckermünde.

The next city on his list was Anklam. Savelli had been there since the Swedish landing. Anklam was on the opposite side of Usedom and could be used by Imperials to cross onto Usedom. However, the Imperials retreated from Anklam too. The king was so surprised he warned General Kagg, whom he sent to take the city, to watch for a trick. Kagg took and fortified the city without problems.

Ueckermünde and Barth (west of Stralsund) were also taken easily. Wolgast was besieged. The garrison surrendered the city but held out in the citadel until August 16. Treptow was also captured.

The king wanted to strengthen his control in the area and connect with Oxenstierna, who had a large force in Prussia. The king told Oxenstierna to send an "able officer" to Stolpe, but connecting with Prussia and Oxenstierna would have to wait. Despite his good position between the Imperial forces, his army was spread out in three separate groups that could only support each other by sea: the king's force at Oderberg and Stettin; Kagg's force on Usedom; and Knyphausen's force at Stralsund. Before advancing inland or joining Oxenstierna, he needed to unite these groups so they could support each other without meeting the enemy. One reason he's called the first "modern general" is his careful attention to communications and keeping his army united. Holding Anklam wasn't enough to ensure the Stralsund force could quickly join his army at Oderburg if needed. The line from Stralsund to Anklam down to Stettin could be broken. The Tollense river (west of Anklam) ran parallel to his line. To secure his coastal gains, he needed to control this river to prevent Imperials from Mecklenburg from cutting his line. To fix this, the king ordered Knyphausen to move his army southwest towards the Tollense. Kagg was to follow Knyphausen, ensuring his northern flank was protected. This spread-out line, with a stronger right flank, would prevent Imperials from supporting each other, as their units would have to hold their positions or risk losing them trying to help another fortified place.

Scottish soldiers, from Lord Reay's regiment, serving Gustavus Adolphus, 1630–31.

Savelli was still at Greifswald. When he learned a small Swedish unit occupied Klempenow, he sent a detachment to observe it. After Wolgast fell, Savelli felt surrounded and marched his army through Demmin to Klempenow. With only 100 men there, Klempenow fell. Only one officer and six men surrendered. To strengthen his hold on the Tollense region, which was now his new defensive line after being driven from Greifswald, he garrisoned Klempenow, Loitz, and Demmin. He also garrisoned Neubrandenburg, Treptow, and Friedland. He ordered Pasewalk taken, a small town outside Stralsund. Despite fierce fighting, it was taken and burned.

Meanwhile, Oxenstierna, stationed at Pasua and Elbing (far east), tried to move towards the king. Key cities for a land route between the two armies were Kolberg (Imperial-held) and Cammin. Knyphausen and Oxenstierna were tasked with creating this land route between Prussia and Swedish Pomerania. It was August, and the king was thinking about winter quarters. However, the Administrator of Magdeburg, Christian William, declared for Sweden, drove out the Imperial garrison, and called for Swedish aid. This happened without the king's knowledge, and he had other priorities. He likely wouldn't have encouraged it. The king still wanted to march to the Elbe, take Mecklenburg, and negotiate with Hamburg and Lübeck. Magdeburg was too far, with many Imperial troops between it and the Swedish army. However, the king sent Colonel Dietrich von Falkenberg to Magdeburg, ordering him to prepare the city for a siege.

This put the king in a tough spot. If he abandoned Magdeburg, other Protestant powers might see him as unreliable and unwilling to support allies. They were already hesitant to help Sweden. If he was seen this way, they would be even less likely to provide support.

Mecklenburg Campaign

The Duchy of Mecklenburg, with Lübeck also shown.

By September 1630, King Gustavus felt secure on the German coast. He wanted to expand west for several reasons: to restore his cousins to their duchies in Mecklenburg (which Ferdinand had taken and given to Wallenstein); to connect with the Duke of Hesse-Kassel, his only true ally in Germany; to reach Magdeburg if possible; to meet the Duke of Saxe-Lauenburg, who promised a warm welcome; and to establish contact with Lübeck and Hamburg. This route, though indirect for Magdeburg, was the only one that avoided invading Saxony and Brandenburg. These princes, who were Protestant, wanted to stay neutral and avoid armies marching through their lands. They were waiting to see who would win and were suspicious of both Swedes and Imperials. They were powerful states and couldn't be easily forced. The king was careful and tried to form alliances with them.

With Magdeburg in mind, and to move towards his allies without invading Saxony and Brandenburg, the king saw that Wismar and Rostock needed to be taken. Wismar was especially important because it would give him more control over the Baltic Sea and prevent enemy fleets from resupplying there. Gustav Horn brought reinforcements from Finland and Livonia. The king left these reserves and most of the Stettin army under Horn, ordering him to hold the area securely, take Greifswald before spring, and protect the Stralsund-Stettin road. If a larger Imperial force attacked, Horn was to abandon Greifswald and protect the main line, marching towards the king.

Swedish ships sailing to take Rostock.

Leaving Stettin on September 9, the king landed at Wolstack and quickly reached Stralsund to prepare for his advance into Mecklenburg. He expected reinforcements from Prussia, but only the Finns and Livonians brought by Horn were available. Sickness was also a problem in the camp, with one in six men sick. From Stralsund, he sailed towards Ribnitz and Rostock, capturing Ribnitz and Damgarten. Here, the king learned an army was gathering at Demmnitz in the east, which worried him, so he gave up his plan to take Rostock for now.

Albrecht von Wallenstein. Born Protestant, he became Catholic and served the Habsburgs well. He was the most skilled general on the Catholic side.

However, something happened that helped Sweden. A meeting had been going on at Ratisbon for six months, and one result was that Wallenstein was fired. Many German rulers disliked him because his troops caused so much trouble in their lands. There was also a rivalry between him and the Elector of Bavaria. One historian said, "The anxiety with which Wallenstein's enemies pressed for his dismissal, ought to have convinced the emperor of the importance of his services... many armies could not compensate for the loss of this individual." But despite his victories, Wallenstein was politically weak. The Emperor's son, Ferdinand, was trying to become the next Holy Roman Emperor. Catholic and Protestant princes wanted Wallenstein gone, and they had power to influence the Emperor. Maximilian's support for his son's election was crucial, so Wallenstein had to be dismissed.

Tilly was given command, but many Imperial soldiers were mercenaries loyal to Wallenstein, not the Emperor. When Wallenstein was dismissed, these mercenaries left. Many joined the Swedish army and quickly learned Swedish discipline. The king thought Wallenstein was so skilled that he even asked him to serve under him. The Catholic side lost a very capable general and an army of 100,000 men loyal to him. Most of the officers in the main Imperial army quit.

Temporary Setbacks

Turning away from Rostock for now, the king decided he must secure the Tollense river. But first, he wanted to settle the Kolberg situation and decided to take it to fully communicate with Oxenstierna. Horn, in command of the Kolberg region, learned of an Imperial plan to march from Garz to relieve Kolberg. Horn gathered all his forces, leaving a small group to watch Kolberg, and marched to Rossentin, south of Kolberg, to wait for the Imperial army. The Imperials tried to avoid detection by taking a long southern route.

Imperial route.

However, their attack was repelled, and they retreated. The Imperials still wanted to relieve Kolberg and planned another surprise move. But this plan lost momentum, and their army became disorganized. Upon reaching the eastern side of his new territories, the king gathered his generals, learned about enemy positions, and decided to attack Garz. Winter was coming, but he wanted to strike a blow against the Catholics before setting up winter camp.

The army moved mostly along the right (east) bank of the Oder towards Gartz. Troops on the left (western) bank stayed in touch with the main army by boat. Moving towards Greifenhagen first, the Imperial general there thought the approaching army was just a Swedish distraction. But the Swedes camped in a nearby forest. The next day, Christmas Day, after religious services, the attack began. A hole was made in Greifenhagen's defenses, and the king personally led the first assault. After taking Greifenhagen, the Imperial troops there retreated towards their comrades in Western Pomerania.

The next day, the king marched his army towards Garz in battle formation, but the Imperials soon retreated south-east. Some units were left to hold Custrin and Landsberg to avoid being cut off from Frankfurt. The king sent units to prevent the Imperial retreat, but he thought Landsberg was too strong to attack. Satisfied with this victory, his army marched back to Neumark Konigsburg.

Positions of Imperial and Swedish armies after the Swedish victory at Garz.

Frankfurt

Having taken Gartz and Greifenburg, which could lead the king through Prussia and Silesia into Ferdinand's lands, the king left Horn with six infantry and six cavalry regiments. These faced the Warta river, ordered to keep the enemy stuck between Landsberg and Küstrin. Horn was told to stay on the defensive against a larger enemy and, if possible, try to take Frankfurt and Landsberg. His reserves were at Pyritz, Stargard, and Gollnow. These were positioned so he could retreat if a larger enemy appeared at Soldin, while also protecting Swedish gains on the Oder's right bank and Eastern Pomerania.

The king set out from Bärwalde to Stettin, crossed there, and gathered 12,000 men. From Stettin, he marched through Germany towards Prenzlau and Neubrandenburg. After taking Neubrandenburg, the Imperial garrison at Treptow also retreated, fearing capture. The next day, Klempenow was taken. These towns were important because they could stop Imperial armies from advancing north to relieve Demmin. By taking Demmin, the king would control the entire Tollense river, a goal he had set earlier but been sidetracked from. Even though it was winter, it was important to establish a strong base between Stralsund and Stettin. With this line secure, his planned expedition into Mecklenburg would be safer.

Demmin was at the meeting point of three rivers, and the ground was swampy. Since it was mid-January, parts of the area were frozen, which helped the Swedes besiege the place. Knyphausen, who was besieging Greifswald, was ordered to come south and help at Demmin. Loitz, a city between Greifswald and Demmin, had to be taken first. The king took it before sitting in front of Demmin and urged Knyphausen to come quickly. Taking Loitz also blocked Greifswald, leaving it without aid.

This move put Tilly in a difficult spot. He wanted to go straight to Mecklenburg, but if he left only his reserves in Landsberg (8,000 men), he feared Horn would push them out and establish the Swedes on the Warta river. If he stayed to protect the Warta line (which, if opened, would give Swedes access to the Austrian Emperor's lands), the Swedes could easily march into Mecklenburg over the Havel and relieve Magdeburg. Tilly thought taking Magdeburg was important for morale and to keep German Protestants under control. Also, Maximilian I, Duke of Bavaria was pushing him from Dresden to strike a decisive blow by taking Magdeburg. Strategically, he wanted to prevent Demmin from being taken. Since the Swedes held all the towns on the direct route between Frankfurt and Demmin, he took a southern detour. This allowed him to move towards his goal and secure a position on the Havel to prevent Swedes from relieving Magdeburg. He also had to march through the Electorate of Brandenburg as carefully as possible. Brandenburg was neutral, but Tilly could demand passage, trying to avoid angering the Elector by bypassing his capital, Berlin. After this "careful" march, he reached Neuruppin. With the Havel behind him, he had achieved one goal: keeping Magdeburg safe. From here, he marched north to help relieve Demmin.

However, Tilly couldn't reach his subordinate in time. After two days, Savelli believed he couldn't hold Demmin and surrendered, on condition that his army not serve in Pomerania and Mecklenburg for three months. The city was well-stocked, expecting a long siege. But since it surrendered quickly, the Swedes gained all the supplies. Among the captured baggage was property of Quinti Del Ponte, a man who had served Sweden but was paid to betray them and deserted. The king was asked what to do with him but said he had no intention of petty revenge.

Battle of Frankfurt an der Oder, by Matthäus Merian.

With so much success in Pomerania, the local leaders finally offered their support to the Swedes. They offered 10,000 infantry and 3,000 cavalry to guard the duchy. This was valuable because it freed up Swedish soldiers for fighting in the field, which was much needed against the large Imperial armies.

Although the king was thinking about wintering his troops, he and Knyphausen believed Tilly was planning to march on Neuruppin to relieve the siege at Greifswald. Since the siege was important, he ordered Horn to march towards Friedland to ensure Knyphausen didn't have to move troops from the siege to stop Tilly from reaching Greifswald.

Kolberg had already fallen, and Gustavus thought Tilly's moves were partly to make up for this loss, which was a blow to the Imperial cause. The king moved back to the Oder, hoping to draw Tilly away from the siege, Stralsund, and Stettin. He considered marching on either Frankfurt or Landsberg. Tilly didn't seem to notice this move. Instead, he marched towards Stargard, south of Neu-Brandenburg. Stargard was not easily defended. The king didn't believe in its strength and told Knyphausen to plan a retreat after a reasonable time. But the messengers were captured, and Knyphausen held out to the last. The city's defenses were broken, and only Knyphausen and three other men survived. The subsequent looting of the city was reportedly terrible.

The positions of the Imperial and Swedish armies after the capture of Landsberg and Frankfurt.

After this siege, which was an Imperial victory, Tilly retreated. He failed to use his victory to his advantage. Seeing this, the king continued his plan towards Frankfurt. However, before advancing, he learned that Imperials had sent a group from Landsberg to Anklam and taken it. Despite this, the king ignored it, which was a very bold move at the time. Even though the king had enemy forces that could easily attack his supply lines, he continued his advance south. Moving from Schwedt, the king moved his force south along the Oder towards Frankfurt.

Arriving at Frankfurt on April 3, 1631, a breach was made in the defenses, and the city was taken. This battle was a clear victory for the Protestant side. On April 5, the king continued his advance. He marched towards Landsberg after driving away Imperial cavalry in the surrounding countryside.

On April 15, the king positioned his army outside Landsberg. Banér, with five regiments from Frankfurt, joined him for the siege. The siege began that same day. There was a strong fortress outside Landsberg, and the king knew he had to take it first. He brought up cannons and fired on the fortress. After a small exchange of artillery fire and one failed enemy attack, the king offered Landsberg strict surrender terms. The next day, the terms were accepted, and the 4,000 Imperial soldiers left the city and fortress, promising not to fight for the next eight months.

Diplomatic Challenges and Magdeburg's Fall

With recent victories, the army's left (eastern) side was secure. The king had two main options: 1. March through Silesia into the Emperor's home lands (Austria) to attack Vienna. This might force the Habsburgs to make peace. 2. March to Magdeburg to relieve the siege and unite with his allies in Mecklenburg.

For some reason, the king didn't choose the first option. He had promised to help Magdeburg. So far, he had only sent a skilled officer to build defenses, train local soldiers, and oversee the city's defense during the siege.

George William, Elector of Brandenburg and Duke of Prussia. His sister was the Queen of Sweden. He tried to stay neutral for much of the Thirty Years' War but couldn't keep his lands out of the conflict. He was one of the German Protestant leaders who didn't fully trust the Swedes.

However, what the king wanted to do proved difficult. If he hadn't fully understood the stubbornness and distrust of the German Protestant rulers towards him before, he soon would. After taking Landsberg and Frankfurt, the king expected Tilly to advance towards these places from Neuruppin via Küstrin. So, he ordered the bridge at Küstrin (which allowed armies to cross the Oder) to be destroyed. Küstrin was part of the Electorate of Brandenburg, and the Prince-Elector of Brandenburg, George William (the king's brother-in-law), felt his neutrality was violated. He was difficult to deal with. Besides his sister being the Queen of Sweden, George William was also a vassal of Gustavus's cousin and enemy, Sigismund III Vasa, as Duke of Duchy of Prussia. This shows how complicated international relations were, made even more complex by personal family ties.

The king wanted to set up his main base at the Spandau Citadel near Berlin for his campaign to the Elbe. This place was also in George William's territory. The king met with George William and asked for control of both Küstrin and Spandau. George William refused, despite their family ties and common Protestant cause. After trying to deal with George William's hesitation diplomatically, the king finally told him that if these places weren't handed over voluntarily, he would take them by force. George William, feeling isolated from both Saxony and the Habsburgs, then agreed to surrender the two places. Even after the king began his advance towards Magdeburg, George William didn't fully give control of Spandau to the Swedes.

Also, Pomerania wasn't providing the promised men and resources to the Swedes. The money for the war, from Sweden and promised allies, wasn't arriving on time. The army had also suffered greatly during the previous winter, especially the cavalry, which was exhausted. The Swedish cavalry was generally not as good as the Imperialists' because of this. Conditions were so bad that soldiers started looting, which the king punished severely.

Having taken Spandau, the king set out towards Magdeburg on May 8. On his way to Dessau, near the border of the Electorate of Saxony, he learned about the problems George William would cause for his operations. There were several routes to Magdeburg, but those south of Saxony were ruined by Imperial occupation, meaning he couldn't feed the army he called "The Army of the Elbe."

Engraving of Johann Tserclaes, "Tilly".

He also didn't have pontoon bridges to cross the wide Elbe River. All boats on the Elbe had been seized by Imperial armies. Given the limited time Magdeburg could hold out and the problems with other routes, Dessau was the best strategic option.

Engraving of John George I, Elector of Saxony.

Because of Saxony and Brandenburg's size and strength, and the problems they could cause for his supply lines if he treated them too harshly, the king had to be careful. He hoped dealing with the Elector of Saxony, John George I, would be easier than with George William. John George had previously supported Ferdinand in the Bohemian revolt, partly because the Emperor gave him the rich province of Lusatia. However, the Habsburgs' aggression against Protestants in Germany, especially after the Edict of Restitution, was clear. John George realized that neutrality wouldn't help him and tried to create a third power in Germany, separate from the Habsburgs and Sweden. He failed and became isolated because of his early support for Ferdinand.

After exchanging messages, some of which were ignored, John George refused the king access to his lands. John George had 40,000 men, who could be used against the Swedes if they didn't treat Saxony respectfully. The king was in a difficult position. Since he thought it was more important to prevent Saxony from joining the Imperials, he didn't march through Saxony towards Dessau.

Sack of Magdeburg. Out of 30,000 citizens, only 5,000 survived.

Magdeburg was in a desperate situation. Initially, only 6,000 Imperial forces were watching the city under Pappenheim, but by mid-April, Tilly brought 25,000 men to take it. Falkenburg had been sent to prepare the city's defenses with the available resources. He had 2,500 men, plus the city militia. But now he faced a much larger force. Despite news of Swedish victories in the east, morale in Magdeburg was low. The city's governor, council, citizens, and a strong Catholic minority were constantly arguing. In early May, Tilly began negotiating with the city. He feared the Swedes would relieve the siege and wanted to take the city quickly. But negotiations didn't finish in time. By May 19, Tilly was so worried he ordered a final assault. He would only accept unconditional surrender. The city council agreed, but Falkenburg asked for a meeting at 4 AM the next morning to talk them out of it. Even though the Imperial negotiator was still in the city waiting for the council's final answer, Tilly ordered the final assault. Many officers and soldiers had left their defensive posts, knowing the council's decision was coming. Falkenburg, hearing of the assault, gathered all the men he could and led a defense. He had some initial success but died defending the city. Shortly after, the city was sacked.

The Elbe River Campaign

When the king heard about Magdeburg's fall, he ordered his forces to retreat towards the Oder. Many blamed the king for Magdeburg's fall, so he issued a statement blaming John George. The king, fearing Tilly would use his victory at Magdeburg, took steps to secure his lands on the Oder. First, he ordered Horn to rebuild the bridge at Schaumberg so he could retreat if needed. Second, he ordered Frankfurt to be heavily fortified.

A map of Germany focusing on the Elbe River.

The king also arranged his army's positions. Banér was in charge of the center, with forces at Brandenburg, Rathenow, Potsdam, Bernau, and Bützow. Fehrbellin was to be the headquarters.

Horn was given the left flank but had only 1,500 men to hold it. After Magdeburg's victory, forces gathered in Silesia to march up the Oder and attack the Swedish left. There was an outpost at Crossen that was sometimes attacked by Imperials. Horn had to take special care of the bridges at Frankfurt, Landsberg, and Schaumberg. The king promised him help from the center if things got difficult. Horn was also to recruit more forces in his area. Soon after, he was ordered to march to Crossen and set up a strong camp there.

While the king was planning his advance at Stettin, the Tsar of Russia, Alexis of Russia, sent a message offering help. The king refused the troops but thanked the Tsar for his friendly offer.

Despite the king's fear of Tilly after his victory, Tilly didn't advance on the Swedes to push them back to the sea. He feared moving east because of the force the Landgrave of Hesse-Kassel, William V, was gathering. William was one of Sweden's only strong supporters. The king had planned to meet him via northern Mecklenburg and combine their forces.

Maximilian I, Elector of Bavaria, Duke and Elector of Bavaria, and president of the Catholic League. He was a skilled politician and gained much from the Thirty Years' War.

Tilly wanted to prevent his forces from being surrounded by Hesse-Kassel in the west and the Swedes in the east. So, Tilly marched north with 17,500 infantry, 7,000 cavalry, and 28 cannons. Along the way, he received 9,000 infantry and 2,000 cavalry from the Catholic League and four regiments from the Spanish Netherlands. Another 25,000 men were marching from Italy but were delayed and only reached the Elbe a year later.

While Tilly was marching, John George made it clear he would resist either side that marched through his territory. Tilly feared Saxony would soon join Sweden, as Protestants were more outraged than scared by Magdeburg's sack.

The king, tired of George William's hesitation, finally decided to force the issue. He marched to Berlin from Spandau and demanded a new treaty from the Elector. The treaty stated that the Swedes would keep Spandau permanently, be allowed to march through Küstrin freely, and receive 30,000 thalers a month from the Elector.

An Imperial group, seemingly lost, was seen outside Malchin. This made the king fear the Imperials would try to relieve the siege at Greifswald. So, he ordered the commander there, Åke Tott, to move all available forces to Greifswald and storm the city. After the Imperial commander was killed in the initial bombardments, the remaining force surrendered on June 25. The king praised Tott and promoted him to field marshal. Tott then advanced into Mecklenburg and restored the dukes whose lands had been taken by the Imperials. However, these dukes also proved to be reluctant allies and were slow to help Sweden. Mirow, Bützow, Schwerin, and Plau were all taken. Only Rostock, Wismar, and Dömitz remained. Many soldiers in these cities chose to join the Swedish army rather than be released or captured.

Banér had been busy securing the Spree–Havel line and took Havelberg while doing so.

Meanwhile, Tilly had been busy enforcing the Emperor's edict of restitution. This was a mistake, as it angered Protestants and divided his own troops. He was ordering German princes to hand over cities and disband their forces, which they were supposedly raising to stay neutral. But Protestant Germany was more outraged than scared by Magdeburg's sack, and these forces were actually being raised to defend against Imperial aggression. From Magdeburg, Tilly marched north towards Hesse-Kassel, capturing Oldisleben and Muhlhausen in June. He also took Gotha, Eisenach, and Weimar. Erfurt paid Tilly to avoid attack. Tilly sent messages to the Landgrave of Hesse-Kassel, ordering him to disband his 6,000 troops. William refused and gathered his forces at Kassel.

Around this time, 8,000 new Swedish reinforcements arrived. 4,000 were sent to the Havel to join the main army. The rest went to Mecklenburg to serve under Tott. Tott was to join the king with an additional 4,000 veterans. During this time, 7,000 English soldiers arrived under the Marquis Hamilton. They arrived at the Peene, not the Weser as expected. The king ordered them to Horn, who was to spread 4,000 of his total force along the Oder line. Horn himself was to bring the rest of his force to join the king.

Having gathered his forces on the Havel, the king moved to the Elbe. With 7,000 infantry and 3,000 cavalry, he went from Brandenburg towards Burg. The king moved towards Jerichow, which made Pappenheim, who Tilly had left at Magdeburg, act.

The Swedes' advance to the Elbe. English reinforcements are shown in yellow.

While the king was at Jerichow, Pappenheim was at Tangermünde, just north on the other side of the Elbe. The king wanted Pappenheim to think he was moving towards Magdeburg, so he started marching that way. Pappenheim, wanting to get there first, marched towards Magdeburg. However, the king immediately turned his army around, marched north, left a few hundred men on the left (western) bank of the Oder, and moved to Tangermünde. The Swedes captured Tangermünde and its fortress, then fortified it. They collected all the boats they could and advanced further north up the Elbe to Werben. Werben was also taken. Fortifications were built at the meeting point of the Havel and the Elbe, near Werben.

Tilly, hearing the news from Pappenheim, advanced his army south to meet the Swedes. They took up position at Wolmirstedt (totaling 27,000 men) north of Magdeburg and sent out three cavalry regiments to observe Werben. The king, by calling in more troops from his commanders to the east and north, gathered 16,000 men.

The king was personally at Arneburg. He decided to gather his cavalry there. After sending a group to scout enemy positions, he moved his forces on the night of August 1. Before reaching Burgstall, he divided his 4,000-man force into three columns. The first column, under the Rheingrave, was ordered to attack Burgstall. The second column was to attack Angern. The king marched with the third column, between the other two, towards Rheindorf.

The Rheingrave's attack was successful, taking Burgstall and seizing all baggage. The column led by the king reached Rheindorf to find Tilly had heard about the other attacks and prepared his army. Even though the king had only 300 men, he led a charge directly into the enemy regiment and broke it. At one point, the king rode into the fight and was surrounded. His life was saved by a loyal captain.

Tilly decided to retreat at this point, moving his army south back to Tangermünde. Horn then arrived with 9,000 reinforcements at Rathenow, which made Tilly, fearing an attack on his flank, move his army back to Wolmirstedt. Between August 5 and 8, when Tilly retreated, he had lost 6,000 men, plus more who deserted after the defeat at Rheindorf.

Tilly's big victory at Magdeburg had been canceled out. He hadn't used his win to push the Swedes back. None of the land losses suffered by the Catholic League and Habsburgs had been recovered. Despite the strategic and morale setback of Magdeburg's fall, the Swedes had strengthened their hold on Germany and achieved a key goal: securing the southern Baltic coast.

Hesse-Kassel and Saxony Join the Cause

The overall strategic situation in Germany in August.

The overall European situation, including Habsburg reinforcements.

Reinforcements arrived for Tilly from Italy. On their march, these new troops forced local princes to submit to the emperor, threatening large fines if they didn't provide soldiers. The recently defeated Tilly, fearing Swedish reinforcements from the east side of the Elbe, positioned himself at Wolmirstedt to be close to Hesse-Kassel, Saxony, and Brandenburg.

The king was at Werben, where he finally met with William of Hesse-Kassel. The Landgrave signed a treaty with Sweden. Weimar, an important city, was also included. These allies agreed to fight the emperor's forces wherever they could. In return, Sweden promised to protect them.

The king left his camp at Werben under Baudissin and Teuffel, with enough troops to defend against any Imperial attack. He then left with 18,000 troops, choosing to operate from the Havel River. His goal was to push Tilly into Saxony, forcing the Elector of Saxony to choose a side. He had little doubt that Tilly, following the emperor's orders, would soon force the Elector's hand. Once the Swedes pushed Imperial forces into Saxony, the king expected the situation to resolve itself. By advancing south from the Havel, he would also be in an ideal position to join forces with the Elector once he made his decision.

Leipzig and Breitenfeld.

In Tangermünde, Tilly told the Hessians they must submit to Imperial rule and disarm. He ordered his soldiers to act harshly. After facing strong resistance from Bernard of Saxe-Weimar, who the king had recently promoted for his successful leadership, they retreated. Tilly's goal was to obey Ferdinand's orders: march to Saxony and force the Elector to disarm and submit. Destroying the region as he went, he set out towards Leipzig. He arrived in Halle on September 4 and continued to Merseburg. He ordered John George to disband his new troops and send a group to serve under him for the Emperor.

Imperial movements as they approached Leipzig. They devastated the region on their way.

Arriving near Leipzig two days later, he ordered John George to supply his army with food and aid.

On September 8, Tilly arrived outside Leipzig and demanded supplies for his army from the duchy's capital. The Elector wasn't in his capital at the moment, but his people were more willing to fight for their city than he was. Tilly devastated the area outside the city and again demanded supplies and housing for his army. He was refused again. The Imperials dug trenches, placed heavy guns at Pfaffendorf (near Leipzig), and fortified hills overlooking roads to the city. This was to block any relief forces, especially from Duben (northeast), where the Swedes might come from. However, the city's residents hadn't received instructions from the Elector, as his messengers couldn't get through. On September 16, they surrendered the city to Tilly. Four hundred thousand florins were to be paid to the Imperials, and the small garrison in Leipzig was allowed to march out with military honors. After occupying the city, Tilly received news that the Swedish and Saxon army was approaching from the North.

Immediately to the North, on September 10, the King finally secured the long-desired treaty from John George. All passes were to be open to the King and closed to the Imperialists. The King agreed to drive the Emperor's forces from Saxony and stand by the Elector to the end. After this treaty, the King ordered all available forces in the area to gather for a major battle. He also prepared a retreat line for himself and the allied army if the battle went badly. Tott was responsible for holding the Swedish communication lines if a retreat was needed. Horn was also to form the core of a new army on the Havel, using troops promised by the Elector of Brandenburg (the King's brother-in-law). The King then crossed the river with his army. He reached Düben on September 15, met with the Elector of Saxony, and inspected his troops. The Elector's army had between 16,000 and 20,000 men. They both returned to the Swedish army and inspected it before holding a war council. After discussing several plans, the council decided to fight Tilly. The Elector was especially eager to get rid of the Imperial army. The Allied army left Düben on September 16 for Walkau. On September 17, the Allied army left Wolkau. After marching for an hour and a half in battle formation, they met the Imperial vanguard on the plain in front of Leipzig.

Battle of Breitenfeld

The Battle of Breitenfeld.

The battle began around noon and lasted over six hours. The first two hours were an artillery duel. The Swedes fired three to five times faster than the Imperials because their cannons were lighter and faster to load. Gustavus had improved his artillery, giving each colonel four mobile, rapid-firing copper cannons. When the artillery stopped, Pappenheim's Black Cuirassiers (heavy cavalry) charged without orders, trying to outflank the Swedish right. Their attack fell between Johan Banér's line and the Swedish reserves. They attacked using a "caracole" (a cavalry maneuver where riders fired pistols and then retreated to reload), but were driven back. They repeated this six more times with little success. Small groups of musketeers placed among the cavalry fired at close range, disrupting the Imperial cavalry and allowing the Swedish cavalry to counterattack effectively. The same tactics worked an hour later when Imperial cavalry attacked the Swedish left flank. After the seventh Imperial attack was pushed back, General Banér led his light (Finnish and West Gaetlanders) and heavy cavalry (Smalanders and East Gaetlanders) forward. Banér's cavalry was trained to use their sabers in close combat, not just pistols, forcing Pappenheim and his cavalry to flee in disorder, retreating 15 miles northwest to Halle.

Battle of Breitenfeld – Opening moves, September 17, 1631. Swedish-Saxon forces in Blue, Catholic army in Red.

During the cavalry charges, Tilly's infantry stayed still. Then, the Imperial cavalry on his right charged the Saxon cavalry and routed them towards Eilenburg. There might have been confusion in the Imperial command about Pappenheim's charge. Military historians wonder if Pappenheim started a double attack or followed Tilly's plan. In any case, seeing an opportunity, Tilly sent most of his infantry against the remaining Saxon forces, marching diagonally across his front.

Battle of Breitenfeld – Stopping the Imperial attack, September 17, 1631. Swedish forces in Blue, Catholic army in Red.

Battle of Breitenfeld – Annihilation, September 17, 1631. Swedish forces in Blue, Catholic army in Red.

Tilly ordered his infantry to march diagonally to the right, focusing his forces on the weaker Saxon flank. The entire Saxon force fled, leaving the Swedish left flank open. Its commander, Gustav Horn, quickly adjusted his line and counter-attacked before the Imperial infantry formations (tercios) could regroup and face the Swedes.

With the Imperial forces busy, the Swedish right and center turned, lining up with Horn. Banér's cavalry, directly led by Gustavus Adolphus, attacked across the former front to hit the Imperial right and capture their artillery. As Tilly's men came under fire from their own captured cannons, the Swedish cannons, under Lennart Torstensson, turned to catch the Imperial tercios in a crossfire.

After several hours of heavy fighting, as sunset approached, the Catholic line finally broke. Tilly and Pappenheim were both wounded but escaped. 7,600 Imperial soldiers were killed, and 6,000 were captured. The Saxon artillery was recaptured, along with all the Imperial guns and 120 regimental flags. As soon as the battle was clearly won, the King dismounted, knelt on the battlefield, and prayed thanks for the victory.

The Swedish king's new military system had proven its worth. The old, slow Spanish tercio system, used for two centuries, was defeated by the faster and more flexible Swedish formations. Also, the importance of infantry was shown again for the first time in a long time. This battle clearly showed that disciplined infantry could withstand a cavalry charge. Furthermore, it proved the value of smaller, more mobile artillery units that could move around the battlefield and aim their own cannons (and captured enemy ones) as needed.

After Breitenfeld: The March to the Main River

Capture of Kreuznach by Swedish troops in February 1632.

After the Swedish victory, there was no more hesitation to join the Protestant cause for fear of Imperial revenge. The King from Sweden had proven he could win major battles and capture strongholds from the Emperor's forces. Since the war began, almost 12 years earlier, Protestants had not been in such a strong position. With the Imperial army destroyed and retreating, most of Germany was open to the Swedish army. The Protestant army had two main strategies: 1. March directly towards the Emperor's home lands (Austria) to attack Vienna. This might force the Habsburgs to make peace. 2. March to the Main and attack the Catholic bishoprics there. This would allow the army to get supplies at the enemy's expense and get revenge for wrongs done to Protestants. From southwestern Germany, they could then attack Bavaria, the main member of the Catholic League, and the Emperor's home lands.

Though more cautious, the second plan was wiser given the circumstances. Even though he had won a great victory, his most powerful allies, the electors of Saxony and Brandenburg, were unreliable. If the Emperor regained momentum, these allies couldn't be fully trusted.

Swedish King Gustavus Adolphus leading a cavalry charge.

Most importantly, the Protestant cause gained confidence, and the Swedish army was inspired by their victories. After this win, there were rumors that Wallenstein might even join the Swedish King. These talks were happening through the English. Several other gains were made. Princes in Anhalt also joined the cause. They signed a treaty promising to pay money, build forts and bridges where the Swedes directed, hold these places for the Protestant cause, deny the Emperor and Catholic League access, and obey the Swedish King. Soon after the victory, these treaties were negotiated at Halle during a conference. The Elector of Saxony and William, Duke of Saxe-Weimar were present, along with many other important allied princes. At this conference, the plan to march on Vienna was discussed a lot. The plan was for the King, with the main army, to march through Thuringia, Franconia, and Swabia. From there, the army would march into Bavaria from its exposed western side. Tilly's army was on the Weser river. The plan to march into southwestern Germany caused intense arguments. Even Richelieu, who financially supported the Swedish campaign, was against it.

Gustavus Adolphus began his new campaign into northern Bavaria by attacking the fortress city of Würzburg on the Main River. His army captured the Marienberg fortress in Würzburg on October 18, 1631. The Swedes and their allies held the fortress until 1635. Adolphus also captured Frankfurt am Main and Mainz by the winter of 1631.

Following this general plan, Baner was ordered to leave a garrison in Landsberg, hand over Frankfurt and Crossen to the Elector of Brandenburg, and take command of the Saxon units once they were ready to fight (their recent quick retreat from Breitenfeld showed they needed a lot of improvement). His overall orders were to capture Magdeburg, secure the western front from all Imperial forces, and hold it.

Swedish Invasion of Bavaria

Siege of Ingolstadt with cannons firing across the Danube river in 1632.

In March 1632, King Gustavus Adolphus of Sweden invaded Bavaria with his Swedish soldiers and German mercenaries.

His next big fight was against Count Tilly at the Battle of Rain on the River Lech in April. This was a major victory for the Swedes, and Count Tilly was badly wounded and died soon after. The immediate result was that Bavaria was open for the Swedish army to occupy. Adolphus planned to move his forces along the Danube River, heading east to capture Neuburg an der Donau and the fortified cities of Ingolstadt, Regensburg, and Passau. This would give the Swedes a clear path to threaten Vienna and the Emperor. However, these fortified cities on the Danube were too strong for Adolphus to take.

Unable to use the Danube route to Vienna, Adolphus began destroying areas deep into southern Bavaria, reaching the gates of Munich. Larger cities were spared from being plundered if they paid large sums of money (like Munich, Augsburg, Freising, and Landshut). However, many smaller villages along the way were looted and burned. Several Bavarian cities and small towns still have records of being looted or destroyed, such as Moosburg, Donauwörth, Indersdorf, Ismaning, Fürstenfeldbruck, and Dachau. The Swedes plundered as far south as the monastery in Andechs and the Irsee Abbey near Kaufbeuren. Neither army went into the Alps.

Many of these towns and villages would suffer from famine and disease about a year later, further reducing Bavaria's population. Maximilian I, Elector of Bavaria, by this time, had fled from his capital in Munich to the safety of Salzburg, which was a neutral area.

While Adolphus occupied Munich in May, the Holy Roman Emperor Ferdinand II called his old military leader Albrecht von Wallenstein back into service to try to stop Adolphus's rampage in Bavaria. Wallenstein quickly raised a new army and marched through northern Bohemia, then into northern Bavaria, to cut off Adolphus's supply lines.

The Battle of Lützen. Engraving by Matthäus Merian, 1632.

Seeing the danger, Adolphus moved his army north to face Wallenstein. Realizing he was outnumbered, Adolphus ordered a tactical retreat into the fortified city of Nuremberg. Wallenstein's army immediately besieged the city to try to starve the Swedes out. In a desperate attempt to break the stalemate, Adolphus attacked Wallenstein's fortified positions in the Battle of the Alte Veste (an old fort near Nuremberg) in late August and the Battle of Fürth in early September, but he failed to break through. The siege ended after several weeks when the Swedes broke out of Nuremberg and fled north. Because both sides were suffering from lack of food and disease, Wallenstein couldn't pursue the retreating Swedes.

Wallenstein met Adolphus again at the Saxon town of Lützen in November 1632. In a major battle, the Swedish army defeated Wallenstein's forces, but King Gustavus Adolphus of Sweden, known as the 'father of modern warfare,' was killed during a confused cavalry charge he personally led.

The Swedish Army (now without King Gustavus Adolphus) returned to Bavaria and captured Regensburg the following year in 1633. However, they lost it again to Imperial forces in 1634. The Swedes were then forced to fight the combined Austrian and Spanish forces at the Battle of Nördlingen (in the Swabian part of Bavaria) in early September 1634. This resulted in a crushing defeat that ended the Swedish phase of the war. In 1638, Maximilian I, Elector of Bavaria, put up a golden statue of the Virgin Mary in Munich to celebrate the end of Swedish occupation. The statue is still in the city center, called Marienplatz, today.

The Swedes appeared in Bavaria one more time in May 1648, joining with the French army to attack the Imperials and Bavarians under Count Holzappel in the Battle of Zusmarshausen near Augsburg. After Holzappel's death and his army's retreat, the Swedes devastated Bavaria again, capturing Freising and Landshut on the Isar. They only began to retreat after failed attacks on Wasserburg and the Bavarian defenses at Mühldorf. Their last small fight was a defeat at Dachau in October 1648, followed by a final Swedish retreat across the Lech River and out of Bavaria. The Peace of Westphalia was signed a few days later, ending the Thirty Years' War.

Images for kids

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  A map showing Europe when Sweden joined the Thirty Years' War and the path of Sweden's campaign.

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  Newspapers showing Sweden capturing many cities.

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  The overall European situation, including Habsburg reinforcements.