By 1437 Khan Ulugh Muhammad lost the struggle for power in the Golden Horde. He was forced to flee and appeared with the small army near the town Belyov, which is in the upper reaches of the Oka river. Initially Grand Duke of Moscow Vasily II, who was indebted to Ulugh Muhammad for the throne of the Grand Duchy, received fugitive Khan rather well and allowed him to nomadize in the vicinity of Belyov.