In 1432 he was dethroned by the supportes of Zygimantas Kestutaitis. Later he sought help from and Livonian Order and Poles, but was defeated in the battle near Lake Zirnajai in 1435.
Svitrigaila, though himself a Catholic, was taking advantage of the dissatisfaction in these provinces which did not share in the privileges of 1387 and 1413 that were reserved to Catholics only.
It is true that in 1434 Svitrigailas rival, Sigismund, issued a new charter of liberties, this time for all parts of the grand duchy without any religious discrimination, and that in the same year the privileges of Polish law and self-government were extended to the Ruthenian lands of the kingdom of Poland.
In agreement with the Metropolitan of Kiev, Svitrigaila first declared in favor of such a religious union, but he later condemned that metropolitan to be burned at the stake because he suspected him of political treason.
In 1392, however, Svitrigaila made an ill-fated attempt to seize neighbouring Vitebsk, but was ousted by his cousin Vytautas of Lithuania to Prussia.
Svitrigaila started his reign by proclaiming full independence of the Grand Duchy from Poland and granting important privileges to his Orthodox subjects.
After his proposals were dismissed, Svitrigaila had to leave the country for ignominious exile in Wallachia, where he was reported to have become a shepherd.