The Grand Duchy of Moscow (Великое княжество Московское) was a medieval Russian polity centered on Moscow between 1340 and 1547. The Grand Duchy of Moscow, as the state is known in Russian records, has been referred to by many Western sources as Muscovy. However, this term is also sometimes applied to the Tsardom of Russia. The Grand Duchy of Moscow was the successor to the Principality of Moscow and the predecessor of the Tsardom of Russia.