Lazar the Serb

Lazar the Serb
Lazar the Serb showing his clock tower to Vasily I of Moscow, miniature from the Illustrated Chronicle of Ivan the Terrible
Born	mid-14th century Prizren, Serbian Empire
Died	after 1404
Known for	Inventing the first mechanical clock in Russia, which was also the country's first public clock
Scientific career
Fields	Invention

Lazar (Serbian: Лазар; Russian: Лазарь), also known as Lazar the Serb or Lazar the Hilandarian^[a] (fl. 1404), was a Serbian Orthodox monk-scribe and horologist who invented and built the first known mechanical public clock in Russia in 1404. The clock, which also struck the hours, was built at the request of Grand Prince Vasily I of Moscow (r. 1389–1425). Prior to his arrival in Moscow, Lazar had served as a monk in the Serbian Hilandar monastery at Mount Athos. The clock tower was located in the palace behind the Cathedral of the Annunciation. However, the clock and the church in which it was located have not survived.