Peter Henlein (also named Henle or Hele) (1485 - August 1542), a locksmith and clockmaker of Nuremberg, Germany is the inventor of the world's first watch. He was the first craftsmen to make small ornamental watches which were often worn as pendants or attached to clothing , known as pomander watches, which are regarded as the first watches in history of timekeeping.

He was especially praised for his ability to create small spring-powered brass clock which were then very rare and expensive. With such popularity, it was not strange that local and distant nobility contacted him on regular basis, demanding ever more beautiful and smaller clock designs. 

As far historical records are concerned, Peter’s first clock was made in 1510, and by 1541 he was well known for his craft and has been tasked on building not only small clocks but also big tower clock for Lichtenau castle.

Even though his spring designs were not particular accurate (they could lose several hours during one day’s work) or even portable (with around 3 inches in size, they were more suited to be worn as a pendant than in pocket), clocks that were made by Peter Henlein soon became sensation in Europe scientific circles and later on by general European population.

Today, Peter Henlein is regarded as a father of modern clocks even though he was not the first locksmith that made small clock designs or was responsible for the discovery of key clock component –mainspring. He died in 1547 knowing that his invention will live forever.

According to en.wikipedia