Sacharias Jansen

1588-c. 1628

Dutch Optician

Sacharias Jansen is generally credited with inventing the first compound microscope and may possibly have invented the telescope. A traveling merchant as well as optician, Jansen was a bit of a rogue, involved as he was in various counterfeiting schemes.

Jansen was born in 1588 in The Hague, Netherlands. His father, Hans, was a lens grinder based in Middelburg, the flourishing capital of Zeeland. Hans died four years after his son's birth, and Sacharias's mother taught her son the skills necessary for managing the family business. Jansen married in 1610, and his son Johannes Sachariassen was born the next year.

It is generally believed that Jansen built the first compound microscope around 1595. Since Sacharias was so young at the time it may have been Hans who actually invented the device, with his son merely having assumed production after his father's death. Jansen's first microscopes had a maximum magnification of only 9X, with images being somewhat blurry. Though not very useful as a scientific tool, knowledge of the principles involved spread quickly and within a few years instrument makers throughout Europe were producing improved devices.

Jansen's role in the invention of the telescope is more controversial. In early October 1608 Hans Lippershay (c.1570-1619) filed a patent claim for the telescope. Shortly thereafter Jansen testified before the Committee of Councillors of Zeeland that he knew the art of making such glasses. A third claimant was Jacob Adriaenszoon of Alkmaar, known as Jacob Metius, who after learning of Lippershay's claim advanced his own. No patent was granted since it was determined the technology was too readily available and easily copied.

Metius claimed to have been perfecting his telescope over the previous two years. Evidence for Jansen's priority is mainly derived from the statements of his son. In 1634 Johannes Sachariassen claimed his father, in 1604, had copied an instrument in the possession of an Italian. In 1655 he claimed his father invented the device in 1590. The latter statement was made during an official investigation into the origins of the instrument and was clearly a self-serving prevarication since Jansen would have been two at the time. The former statement has more to recommended itself, as it was made during casual conversation. However, even if Jansen did invent the telescope in 1604, the question stands as to why it remained a secret.

The most likely explanation is that while Jansen probably did copy an instrument in 1604 —consisting of a concave and convex lens in a tube that provided a slight magnification—it was not used as a telescope. Giambattista della Porta (1538-1615) and others seem to have possessed similar instruments that they used to improve faulty vision. This was the typical use for such devices.

A likely scenario is that after Jansen and Metius learned of Lippershay's instrument they realized they were in possession of the same device, which they had been using for other purposes. They then laid claim to the invention as their own. While it may never be known who first realized such a device could be used to enhance normal vision for viewing objects at a distance, it remains certain that the earliest mention of a telescope is in connection with Lippershay's patent application.

On April 22, 1613, Jansen was fined for counterfeiting copper coins. He moved to Arnemuiden, where he expanded his operation to include gold and silver coins. After being apprehended in 1618 he escaped to Middelburg to avoid a death sentence. Financial difficulties followed, leading to bankruptcy in 1628 and the subsequent sale of property to settle his debts. He died sometime before 1632.

STEPHEN D. NORTON