The Great Feudal War
The subjugation of the Rus' provinces by the Golden Horde in the 13th century had left a set of relatively smaller and weak principalities fighting amongst themselves. By 1380, with Dimitry Donsky's defeat of the Golden Horde in the Battle of Kulikovo, the Duchy of Moscovy stood as one of the stronger regional powers.
In 1389, Donsky died, leaving his son Vasily (Vasily I) as successor, with the stipulation that if Vasily were to die, then Vasily's brother Yuri would be named Grand Prince. However when Vasily died in 1425, he named his son Vasily (Vasily II) successor. Yuri thus became a pretender to the throne, fleeing to the principality of Galich. In 1433, Yuri's army defeated the forces of Vasily II, allowing Yuri to claim the throne of Moscovy. Yuri, however, died shortly thereafter, leaving his son, also named Vasily, as successor. Vasily Yurivech's brothers and cousins refused to lend him any support, preferring instead to support Vasily II. In 1436 Vasily Yurivech was defeated in battle and imprisoned.
By 1444, Vasily II had most of the Muscovy princes under control -- the exceptions being Tver, Ryazan, and Novgorod. Vasily Yurivech's brother, Dimitri Shemyka, had sworn fealty to Vasily II and was given an army to command to subjugate Tver and Ryazan.
In 1446, Tver capitulated and the administration of the principality was given over to the prince of Yarolslav.
Shortly thereafter, Ryazan also acknowledged the suzerainity of Moscovy.
The First Tartar Wars
Ever since the defeat of the Golden Horde by Dimitry Donsky, the power of the Horde over Muscovy has been waning. Still, in the mid-15th century, Muscovy was ostensibly a subject of the Kahnate. So perhaps as a curb to the growing Muscovy independence, the Golden Horde also declared war over Ryazan. Which meant if Muscovy wanted to claim Ryazan as a subject, they would need to defeat the Golden Horde and throw off that yoke once and for all.
In December 1446 in Tula, near the Kulikovo fields where Vasily's grandfather had first defeated the Horde, Dmitry Shemiaka lead the Muscovy forces into battle against the Khanate.
The Muscovy victory was clear if not decisive.
Shemiaka pursued the retreating Horde forces south, catching up to them at the Volga river near Sarai. This time the Khan's army was completely destroyed.
In the meantime, sensing a weakness in their neighbors, the Crimean khanate (in alliance with the Kazan and Nogai) invaded the Golden Horde from the south.
By November of 1447, Muscovy was in control of the northern part of Golden Horde lands, from Ryazan to the Volga river. While the Crimeans were making progress in the south.
In February of 1448, the Golden Horde agreed to a treaty with Muscovy, giving Ryazan administration over the territories up to the Volga basin (modern day Volgograd).
The situation in Central and Eastern Europe after the conclusion of the Muscovy feudal wars and the First Tartar War.
