Ulugh Muhammad first came to power following the death of
Yeremferden. His main competitor for control of the Horde was his cousin
Dawlat Berdi, the son of Yeremferden. For much of his reign Ulugh Muhammad controlled
Sarai, and was therefore seen as the most legitimate ruler within the Horde, although Sarai was captured by his rival after the
Siege of Sarai in 1420 and held by him for two years. In 1422
Baraq Khan defeated both Ulugh Muhammad and Dawlat and drove them out of the country. While Dawlat remained in
Crimea, Ulugh Muhammad fled to the
Grand Duchy of Lithuania and pled for assistance from
Vytautas the Great. With this assistance, he was able to march on Baraq and recapture Sarai. After regaining control over the Khanate, Ulugh Muhammad marched on Crimea, where Dawlat Berdi had re-established himself following Baraq's defeat and death. After a series of indecisive skirmishes his invasion was cut short due to the death of Vytautas, which forced Ulugh Muhammad to concentrate his forces on Lithuania, where he supported
Sigismund Kęstutaitis against
Švitrigaila in the fight for the Lithuanian throne. Švitrigaila, in turn, supported
Dawlat Berdi and later
Sayid Ahmad I, as did
Vasili II of Moscow. ==Kazan==