What contributions of Hans and zacharias janssen and date of its contributions?

Hans and Zacharias Janssen, Dutch spectacle makers, are credited with the invention of the compound microscope around 1590. Their contributions laid the groundwork for advancements in microscopy, allowing for the observation of microorganisms and cellular structures. This innovation significantly impacted scientific research and exploration in Biology and medicine. Their work marked a pivotal moment in the development of optical instruments.