Born Feb. 18, 1690; died June 26, 1718. Tsarevich, eldest son of Peter I by his first wife, E. F. Lopukhina.
Up to the age of eight, Aleksei’s education was directed by his mother in an environment hostile to Peter I. In 1705–06, a group of boyars and clergy opposing Peter I’s reforms formed around the tsarevich. In October 1711, Aleksei Petrovich married Princess Sofia Charlotte Brunswick-Wolfenbüttel (died 1715), who bore him a son, Peter (later Peter II, 1715–30). Peter I repeatedly demanded that Aleksei Petrovich break with the reactionary clergy and opponents of Peter’s reforms; he threatened to deprive Aleksei Petrovich of his right of succession and to cloister him. At the end of 1716, fearing punishment, Aleksei Petrovich fled to Vienna, under the protection of the Austrian emperor, Charles VI. He hid in the castle of Ehrenberg in Tyrol and then, from May 1717, in Naples. By threats and promises, Peter I got him to return in January 1718 and forced him to renounce his right to the throne and to betray his confederates. On June 24, 1718, a supreme court of high military officials, senators, and representatives of the Synod sentenced Aleksei Petrovich to death. According to an extant version, he was strangled by a retainer of Peter I in the Peter and Paul Fortress.