M icroscopes have always been a crucial tool used for the advancement of health and medicine. They allow medics, scientists and researchers to describe the body at a microscopic level more consistently and with confidence in what they see through them. Today microscopes are used in the observation of bacteria and microbes as well as in the development of new chemicals and medicines used to combat disease. RCSI Heritage Collections holds a large collection of microscopes dating back to the early 19 th century. Here, we take a ‘closer’ look at the history of the microscope, how they came about, as well as their introduction to Irish medical science (there’s an RCSI link!) History It was a Dutch father-son team named Hans and Zacharias Janssen who invented the first so-called compound microscope in the late 16th century when they discovered that, if they put a lens at the top and bottom of a tube and looked through it, objects on the other end became magnified. However, as ing