Trezzini was one of the first architects to be hired by Peter I (reigned 1682-1725) as part of the Tsars policy to modernize Russia. He arrived in Moscow in September 1703 with nine other craftsmen, and after working on sites there and on the Baltic, he settled in St Petersburg in 1706. His first five years there were centred on developing the Peter and Paul Fortress on an island by the north bank of the River Neva. He often referred to himself as the architect of the St Petersburg Fortress, since his work there lasted for almost 30 years. From 1706 he supervised the rebuilding of the earthworks in masonry, and the construction of bastions in a layout influenced by Sebastien Leprestre de Vauban. The Peter Gates (1717-1718) at the main entrance of the fortress and a triumphal arch with low-relief decoration are among his surviving creations.