Who invented the simple microscope?

The invention of the simple microscope is often attributed to Zacharias Janssen, a Dutch spectacle maker, around the late 16th century. However, this attribution is somewhat debated, as there is limited historical evidence. Some sources suggest that Zacharias Janssen and his father, Hans Janssen, may have collaborated in its creation.

Antonie van Leeuwenhoek, although not the inventor, is the most famous early user of the simple microscope. He significantly improved the design and used it to make groundbreaking discoveries in microbiology during the 17th century.

So, while Janssen is generally credited with the invention, van Leeuwenhoek is credited with its development and widespread scientific use.