The pocket watch was developed by German inventor Peter Heinlein, who developed the first wave of pocket watches in 1524. However, early watches were worn as a pendant around the neck. Charles II popularized putting watches in pockets in 1675.
Heinlein was the first to produce watches not requiring falling weights as a source of power. Heinlein's first wave of pocket watches were round and bulky. After the screw was developed in the 1550s, watches became flatter. In 1675, Charles II of England set the trend, creating a new fashion style of carrying watches in pockets rather than as neck pendants. Pocket watches prior to the 1750s were not accurate, losing hours every day; however, the development of lever escapement reduced the time error on watches to just one to two minutes per day.