In 1604, Dutch optician Zacharias Janssen is recognized as the inventor the compound microscope. Though rudimentary, the Janssen microscope was an important advance from contemporary use of a single lens for magnification purposes.

However, because the accomplishment is generally agreed among historians to be dated in the 1590s, most scholars believe that his father, Hans, must have played an important role in the creation of the instrument.

The pair worked together as spectacle makers in Middleburg, Holland not far from Hans Lippershey, another optical scientist who is often alternatively credited with the invention of the microscope.