Jia Dan facts for kids
Jia Dan (simplified Chinese: 贾耽; traditional Chinese: 賈耽; pinyin: Jiǎ Dān, 730 – 805) was a very smart Chinese official during the Tang dynasty. He was a great mapmaker, a military leader, and a politician. He was known for his amazing knowledge of geography and for creating huge, detailed maps of China and other countries.
Background
Jia Dan was born in 730, when Emperor Xuanzong of Tang was ruling. His family came from Cang Prefecture, which is now Cangzhou, Hebei province. His family had a long history of serving as government officials. Both his grandfather and father also worked as officials in local government.
Career
Starting His Career
During Emperor Xuanzong's time (742–756), Jia Dan passed important government exams. This allowed him to become a sheriff in Linqing County. He later moved to Zhengping County. This was seen as a promotion because it was closer to the capital city, Chang'an.
He then worked for a military governor named Wang Sili. Jia Dan was promoted to deputy mayor of Taiyuan. He also served as the prefect of Fen Prefecture for seven years. People knew him for ruling the area very well.
Jia Dan was later called back to Chang'an. He became the minister of vassal affairs. This job meant he met and entertained foreign visitors. He also handled imperial funerals and commanded some imperial guards.
Meeting foreign envoys helped Jia Dan learn a lot about other countries. He gathered information about their cultures and geography. Historians believe this is how he gained his amazing knowledge of foreign lands. In 779, he became the prefect of Liang Prefecture. He also became the military governor of Shannan West Circuit.
During Emperor Dezong's Reign
In 781, during the rule of Emperor Dezong of Tang, Jia Dan helped fight against a rebel general named Liang Chongyi. Jia Dan's forces captured Jun Prefecture. After Liang's defeat, Jia Dan became the military governor of Shannan East Circuit. In 783, he also helped fight another rebel, Li Xilie.
In 784, Emperor Dezong had to flee to Liang Prefecture because of rebellions. Jia Dan sent an officer, Fan Ze, to report to the emperor. Suddenly, an order came saying Fan Ze was the new military governor. Jia Dan was called back to serve as the minister of public works.
Jia Dan was hosting a party when the order arrived. He acted as if nothing had happened. After the party, he told Fan Ze about his promotion. He immediately started handing over his duties. One of his officers, Zhang Xianfu, was very angry. He thought Fan Ze had tricked Jia Dan. Zhang wanted to kill Fan Ze.
Jia Dan stopped him. He explained that Fan Ze had the emperor's approval. This meant Fan Ze was the rightful military governor. That same day, Jia Dan left his post. He took Zhang with him to prevent any more trouble. Jia Dan soon became the defender of the eastern capital, Luoyang.
In 786, Jia Dan became the military governor of Yicheng Circuit. At this time, Li Na, a neighboring military governor, was seen as a threat. Li Na had rebelled before but had rejoined the emperor's side.
Once, soldiers from Li Na's area were passing through Jia Dan's territory. Jia Dan's officers worried they might cause trouble. They suggested keeping the soldiers outside the city walls. But Jia Dan said it was wrong to make soldiers rest outside. He welcomed them inside the city. The soldiers did not cause any problems.
Jia Dan also often hunted near Li Na's borders. He would even go into Li Na's territory. Li Na was pleased that Jia Dan trusted him. He admired Jia Dan's openness. Because of this, Li Na never attacked Jia Dan's area.
In 793, Jia Dan was called back to Chang'an again. He became a high-ranking official called You Pushe. He was also made a chancellor. He worked with other important officials like Lu Zhi.
In 800, a military governor named Lu Qun died. Jia Dan suggested that Emperor Dezong choose a new governor without asking the local officers first. He believed asking them showed weakness. The emperor agreed. He directly appointed Li Yuansu as the new military governor.
In 801, Jia Dan finished a huge 40-volume book. It included a large map of China and other countries. It also described different parts of Tang China and foreign nations. Emperor Dezong rewarded him with silk, silver, and a horse. He also made him the Duke of Wei.
Later Years
In 805, Emperor Dezong died. His son, Emperor Shunzong of Tang, became emperor. Emperor Shunzong was very ill. A close friend of the new emperor, Wang Shuwen, became very powerful. Jia Dan did not like Wang Shuwen and his friends. He offered to retire, but Emperor Shunzong did not let him.
Jia Dan died later that year. By then, Emperor Shunzong had given the throne to his son, Emperor Xianzong of Tang. Jia Dan was given special honors after his death. People said that even though he didn't make big policy changes as chancellor, he was a good and honest leader.
Works
Jia Dan was very important for studying geography in China. His writings about foreign countries are especially notable. He started collecting information for his books as early as 784. He asked Chinese and foreign visitors about the geography, origins, and customs of other lands. He made sure all foreigners were questioned and their answers recorded carefully.
He paid special attention to countries along trade routes by land and sea. Because of his efforts, knowledge of countries outside China greatly improved. He created several geography works. These included the 10-volume Huanghua Sida Ji and the 40-volume Gujin Junguo Xiandao Siyi Shu. He also made a map called Hainei Huayi Tu, which means "Map of Chinese and non-Chinese Territories in the World."
This map showed China and other countries. It even included former Chinese areas in Central Asia that were lost to the Uyghurs and Tibetans. The Huanghua Sida Ji was given to Emperor Dezong of Tang in 798. Both the 40-volume book and the map were given to the emperor in 801.
When finished in 801, the map was huge! It was about 9.1 meters (30 feet) long and 10 meters (33 feet) tall. It used a grid scale where one inch on the map equaled one hundred li (a Chinese unit of distance). This amazing map is now lost. However, a later map from 1136, called the Huayi tu, has names of foreign places. These names were taken from Jia Dan's map.
In his 40-volume work from 801, Jia Dan wrote about two main sea trade routes. One went from the coast of the Bohai Sea to Silla in Korea. The other went from Guangzhou, through Malacca, to the Nicobar Islands, Sri Lanka, and India. It continued along the eastern and northern shores of the Arabian Sea to the Euphrates River.
Korean ships were very active in the Yellow Sea trade. Most Japanese ships had to travel south to places like Hangzhou Bay. Jia Dan's book has some of the most accurate descriptions of the Arab world from Tang Chinese sources. He wrote that ships in the Euphrates River had to anchor at its mouth. Then, they transferred goods by land to the capital of Dashi Guo (the Abbasid capital, Baghdad).
An Arab merchant named Shulama confirmed this. He noted that Chinese junk ships were too deep to enter the Euphrates. So, they had to move passengers and cargo onto smaller boats. A small part of this second trade route even reached Dar es Salaam in Tanzania, East Africa.
In his work written between 785 and 805, he described the sea route into the Persian Gulf. He wrote that the medieval Iranians had built 'ornamental pillars' in the sea. These pillars had torches at night. They acted like lighthouse beacons for ships that might get lost. Arabic writers, like al-Mas'udi, confirmed Jia Dan's reports about lighthouses in the Persian Gulf a century later.
