The earliest known watches were made in Germany at the beginning of the 16th century. They were scaled-down versions of the slightly earlier table clocks and were made of iron throughout. This is an example of a spring-driven verge escapement watch movement, which would have been used in one of these early drum watches. It is fitted with a stackfreed regulator, which helps to control the rate at which the spring unwinds by friction. The watch would have been wound each day by hand.
© Science Museum / Science & Society Picture Library