Since around 1200, people would lay hemispheres of glass or gemstone (rock crystal, beryl) directly on a text to magnify it. As early as the 13th century, these reading stones developed into magnifying glasses, convex lenses with a handle held up before a reader’s eye. Despite durable legends and historical falsifications, the date of the invention of spectacles and the identity of the inventor are still unknown. At the end of the…