Vasily I Dmitriyevich was the Grand Prince of Moscow, heir of Dmitry Donskoy. He ruled as a Golden Horde vassal between 1389-1395, and again in 1412-1425. The raid on the Volgan regions in 1395 by Mongol emir Timur resulted in a state of anarchy for the Golden Horde and the independence of Moscow. In 1412, Vasily reinstated himself as a vassal of the Horde. He had entered an alliance with the Grand Duchy of Lithuania in 1392 and married the only daughter of Vytautas the Great, Sophia, though the alliance turned out to be fragile, and they waged war against each other in 1406–1408.
While still a youth, Vasily, who was the eldest son of Grand Prince Dmitry Donskoy, travelled to the Tatar khanTokhtamysh to obtain the Khan's patent for his father to rule the Russian lands as the grand prince of Vladimir. Diplomatically overcoming the challenge of the prince of Tver, who also sought the patent, Vasily succeeded in his mission. But he was subsequently kept at Tokhtamysh's court as a hostage until 1386 when, taking advantage of Tokhtamysh's conflict with his suzerain Timur Lenk, he escaped and returned to Moscow. Vasily I continued the process of unification of the Russian lands: in 1392, he annexed the principalities of Nizhny Novgorod and Murom. Nizhny Novgorod was given to Vasily by the Khan of the Golden Horde in exchange for the help Moscow had given against one of his rivals. In 1397–1398 Kaluga, Vologda, Veliki Ustyug and the lands of the Komi peoples were annexed. To prevent Russia from being attacked by the Golden Horde, Vasily I entered into an alliance with the Grand Duchy of Lithuania in 1392 and married Sophia of Lithuania, the only daughter of Vytautasthe Great. The alliance turned out to be fragile, and they waged war against each other in 1406–1408. Mongol emir Timur raided the Slavic lands in 1395; he ruined the Volgan regions but did not penetrate as far as Moscow. Timur's raid was of service to the Russian prince as it damaged the Golden Horde, which for the next twelve years was in a state of anarchy. During the whole of this time no tribute was paid to the khan, Olug Moxammat, though vast sums of money were collected in the Moscow treasury for military purposes. In 1408 Edigu burnt Nizhny Novgorod, Gorodets, Rostov, and many other towns but failed to take Moscow, though he had still burnt it. In 1412, however, Basil found it necessary to pay the long-deferred visit of submission to the Horde. The growing influence of Moscow abroad was underlined by the fact that Vasily married his daughter Anna to Emperor John VIII Palaeologus of Byzantium.
Domestic policy
During his reign, feudallandownership kept growing. With the growth of princely authority in Moscow, the judicial powers of landowners were partially diminished and transferred to Vasily's deputies and heads of volosts. Russian chronicles speak of a monk, Lazar the Serb, newly arrived from Serbia, inventing and building a clock on a tower in the Grand Prince's palace in Moscow behind the Cathedral of the Annunciation at the request of Vasily I, in 1404. It was the first ever mechanical clock in Russia, and also the country's first public clock. It was among the first ten such advanced clocks in Europe, and was regarded as a technical miracle at the time. The most important ecclesiastical event of the reign was the elevation of the Bulgarian, Gregory Tsamblak, to the metropolitan see of Kiev by Vytautas, grand-duke of Lithuania; the immediate political consequence of which was the weakening of the hold of Moscow on the south-western Russian states.
Marriage and children
Vasily married Sophia of Lithuania, a daughter of Vytautas the Great and his wife, Anna. They had nine known children:
Ivan Vasilievich, husband of a daughter of Ivan Vladimirovich of Pronsk.
Anastasia Vasilievna, wife of Vladimir Alexander, Prince of Kiev, son of Vladimir Olgerdovich
Daniil Vasilievich.
Vasilisa Vasilievna. Married first Alexander Ivanovich "Brukhaty", Prince of Suzdal and secondly his first cousin Alexander Daniilovich "Vzmetenj", Prince of Suzdal. They were both fifth-generation descendants of Andrei II of Vladimir.
Simeon Vasilievich
Maria Vasilievna. Married Yuri Patrikievich, son of Patrikej, Prince of Starodub and his wife Helena. The marriage solidified his role as a Boyar attached to Moscow.