Сигизмунд Кейстутович
When Sigismund seized power in Lithuania by staging a coup in 1432, Lithuania split into two opposing camps, and there began three years of devastating hostilities. To prevent the Knights from continuing their support of Švitrigaila, Poland backed a Hussite invasion of Prussia in 1433. The war ended in a decisive defeat for Švitrigaila and his ally, the Livonian branch of the Teutonic Knights, at the Battle of Pabaiskas in September 1435. Švitrigaila eventually surrendered in 1437; Sigismund Kęstutaitis ruled Lithuania for only eight years before he was assassinated in 1440.