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Zacharias Janssen
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Zacharias Janssen
Born 1585 (1580)
Died Given as before 1632 (sometimes 1638)
Nationality Dutch
Other names Zacharias Jansen, Sacharias Jansen
Occupation Spectacle-maker (sometimes counterfeiter)
Known for Possible inventor of the microscope and the telescope (posthumous claim)
Parents
  • Han Mertens (father)
  • Mayken Provoost Bacher (mother)

Zacharias Janssen (also known as Zacharias Jansen or Sacharias Jansen; 1585 – before 1632) was a Dutch person who made eyeglasses. He spent most of his life in Middelburg. Many people believe he invented the first optical telescope and the first true compound microscope. However, these claims were made many years after he died and are still debated today.

About Zacharias Janssen

Zacharias Janssen was born in The Hague, a city in the Netherlands. Records suggest he was born in 1585, though some say it could have been as early as 1580 or as late as 1588. His parents were Hans Martens and Maeyken Meertens. They likely came from Antwerp, Belgium.

Zacharias grew up in Middelburg with his sister Sara. At that time, Middelburg was a very important city in the Netherlands. He was known for having some difficulties with local authorities.

In 1610, Zacharias married Catharina de Haene. They had a son named Johannes Zachariassen in 1612.

Becoming a Spectacle Maker

In 1615, Zacharias became the guardian for two children of a spectacle maker named Lowys Lowyssen. It is thought that Zacharias also took over Lowys Lowyssen's tools for making eyeglasses. The first time Zacharias Janssen was officially recorded as a spectacle maker was in 1616.

In 1618, his family had to move to Arnemuiden because Zacharias faced some legal issues. He later returned to Middelburg in 1621.

After his first wife passed away in 1624, Zacharias married Anna Couget. She was from Antwerp. In 1626, he moved to Amsterdam, still working as a spectacle maker. Zacharias Janssen is believed to have died before 1632.

The Telescope and Microscope Claims

For many years, people have claimed that Zacharias Janssen invented the telescope and/or the microscope. These inventions are said to have happened in Middelburg between 1590 and 1618. Zacharias worked in the competitive business of making eyeglasses. He even lived next door to another spectacle maker, Hans Lippershey, who also claimed to have invented the telescope.

It's hard to say for sure who invented these tools first. There isn't clear proof, and there are many confusing stories from his son and other people from that time.

The Investigation by Willem Boreel

The idea that Zacharias Janssen invented the telescope and microscope became popular around 1655. A Dutch diplomat named Willem Boreel started an investigation to find out who truly invented the telescope. He asked a local official in Middelburg to look into it.

This official spoke with Johannes Zachariassen, Zacharias Janssen's son. Johannes swore that his father invented both the telescope and the microscope as early as 1590. He also claimed that Hans Lippershey had stolen his father's idea for the telescope. This story seemed believable to Boreel, who then thought Zacharias Janssen was the inventor he remembered.

The Microscope Claim

Johannes also claimed that his father, Zacharias Janssen, invented the compound microscope in 1590. However, Zacharias would have been only 2 to 5 years old at that time. Because of this, some historians think that Zacharias's grandfather, Hans Martens, might have been the actual inventor.

Over the years, other claims have come forward. In 1822, physicist Jean Henri van Swinden's research supported Janssen's claim. In 1841, a collector named Zacharias Snijder found four iron tubes with lenses. He said these were original telescopes made by Janssen.

Historian Cornelis de Waard found a note from 1634 by the Dutch philosopher Isaac Beeckman. In this note, Beeckman mentioned that Johannes Zachariassen claimed his father made his first telescope in 1604. Johannes said it was a copy of an Italian device from 1590.

Historical Records and Legacy

Much of what we know about Janssen's life comes from investigations done before World War II. Sadly, many of the original records in Middelburg were destroyed during a bombing in 1940. Without these earlier studies, we would know very little about Zacharias Janssen.

What is Named After Him?

The planet 55 Cancri e, which is a type of planet called a "super-Earth," is named "Janssen" to honor him.

See also

Kids robot.svg In Spanish: Zacharias Janssen para niños

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