Boris of Tver

Boris of Tver or Boris the Great (ca. 1399–February 10, 1461) was a Grand Prince of Tver from April 22, 1426 to his death. Biography Domestic and foreign politics The year 1425 was devastating for the Principality of Tver. After the sudden death of Vasily I of Moscow, in the same year plague killed three Grand Dukes of Tver: Ivan Mikhailovich, Boris' father Aleksander Ivanovich and brother Jury Aleksandrovich. Thus Boris Aleksandrovich became the ruler of the principality. At the beginning of his reign the muscovite Grand Prince Vasily II was very young, so the power was concentrated in hands of his warden Vytautas. That was the last chance for Tver to prevent Moscow from complete dominance. In 1427 Boris I came to service of Vytautas together with Ivan III of Ryazan, still staying the ruler of Tver. However, in 1430 Vytautas died and the Grand Duchy of Lithuania immensed in the internal strife. Meanwhile in Rus' started the Muscovite Civil War, that weakened the Moscow princes and let the Principality of Tver more independence.