Zacharias Janssen

Over the years there have been claims Zacharias Janssen invented the telescope and/or the microscope in Middelburg between 1590 and 1618. Zacharias worked for some period of his life as spectacle-maker, spectacle-making being a very competitive and secretive trade, and at one time lived next door to Middelburg spectacle maker Hans Lippershey, also claimed to have invented the telescope. Janssen’s attribution to these discoveries is debatable since there is no concrete evidence as to the actual inventor, and there are a whole series of confusing and conflicting claims from the testimony of his son and fellow countrymen.

The claim that Zacharias Janssen invented the telescope and the microscope dates back to the year 1655. During that time Dutch diplomat Willem Boreel conducted an investigation trying to figure out who invented the telescope. He had a local magistrate in Middelburg follow up on a 45-year-old recollection of a spectacle maker named “Hans” who told a young Boreel in 1610 about inventing the telescope. In his investigation, the magistrate was contacted by a then-unknown claimant, Middelburg spectacle maker Johannes Zachariassen, the son of Zacharias Janssen, who testified under oath that his father invented the telescope and the microscope as early as 1590 and that Hans Lippershey had stolen his father’s invention of the telescope. This testimony seemed convincing to Boreel, who modified his recollections, concluding that Zacharias must have been who he remembered. Boreel’s conclusion that Zacharias Janssen invented the telescope a little ahead of spectacle maker Hans Lippershey was adopted by Pierre Borel in his 1656 book on the subject.

In Boreel’s investigation, Johannes also claimed his father, Zacharias Jansen, invented the compound microscope in 1590. This pushes the date so early it is sometimes assumed, for the claim to be true (Zacharias most likely dates of birth would have made him 2-5 years old at the time) his grandfather, Hans Martens must have invented it.

Other claims have come forward over the years. Physicist Jean Henri van Swinden’s 1822-23 investigation reached the conclusion supporting Janssen and in 1841 a collector named Zacharias Snijder came forward with 4 iron tubes with lenses in them purported to be Janssen original telescopes. In historian Cornelis de Waard’s 1906 book on the history of the telescope, he recounted his discovery of note written in 1634 by the Dutch philosopher Isaac Beeckman in which Beeckman mentioned that Johannes Zachariassen claimed his father created his first telescope in 1604 (and that it was a copy of an Italian device from 1590). The German astronomer Simon Marius’s account to his patron Johan Philip Fuchs von Bimbach about meeting an unnamed Dutchman at the 1608 Autumn Frankfurt Fair who tried to sell him a device that sounded like a broken telescope has led to later speculation this unnamed Dutchman could have been Zacharias Janssen.