Lazar the Hilandarian

Lazar, also known as Lazar the Serb or Lazar the Hilandarian, 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. 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.