a Dutch spectacle-maker from Middelburg associated with the invention of the first optical telescope. Janssen is sometimes also credited for inventing the first truly compound microscope. However, the origin of the microscope, just like the origin of the telescope, is a matter of debate. Over the years there have been claims Zacharias Janssen invented the telescope and/or the microscope in Middelburg between 1590 and 1618.
