The late Middle Ages saw some technical innovations which have had a lasting impact; today we cannot imagine life without them. Spectacles enabled weak sight to be improved or corrected, with the result that the books and documents circulated on a large scale as a consequence of the invention of printing could also be read by people with defective vision. Mechanically operated clocks on town halls and church towers became important fixed points in the lives of people in towns and villages. They became an essential element of order in everday life and changed people’s relationship with time. Telescopes, which were developed in the sixteenth century from so-called ‘reading stones’, provided a new view of the world.