Hans and Zacharias Janssen were a Dutch father and son accredited with the creation of the first microscope. Both lived in the Netherlands and were working with each other as spectacle makers.
Hans and Zacharias created the first microscopes through experimenting with different lenses placed at the ends of tubes. Zacharias is typically given credit as the creator of the first microscope, but his birth records suggest his father played an essential role in its creation due to his young age. Records detailing Zacharias' life were destroyed during the bombing of Middelburg by the Germans during World War II.
The most well-known version of their microscope was an adjustable sheath consisting of three different tubes with a bi-convex lens as the eyepiece and a plano-convex objective lens. The lenses were placed at the ends of the tube. Adjusting the tubes allowed for magnification of an item up to ten times its size. It was intended as a hand-held device. The design was considered highly complex, when it was created, and served as the basis of future microscope technology. Anton van Leeuwenhoek and Robert Hooke improved on the design in the 17th century, allowing for the observation of objects as small as diatoms and individual cells.