The magnifying glass was invented in 1250 by Roger Bacon. As a lecturer at the University of Oxford, Bacon conducted many experiments with mirrors that explained the principles of reflection and refraction. He was known as Doctor Mirabilis, which is Latin for "wonderful teacher."
Although Bacon is credited with first discovering the properties of the convex lens, optical devices to make objects appear bigger have been used for thousands of years. In ancient Egypt, clear pieces of crystal were used to see small objects more clearly. Similarly, Roman Emperor Nero used clear gemstones to peer at faraway actors on stage.