A royal succession crisis in 1430 triggered a brutal six-year Lithuanian civil war.
When Vytautas the Great died without an heir in 1430, the Grand Duchy of Lithuania fractured. Two rival claimants, Švitrigaila and Sigismund Kęstutaitis, dragged the state into a devastating conflict, pulling in the Teutonic Knights, Poland, and even Hussite crusaders in a struggle that reshaped the region's power dynamics.
The death of Vytautas the Great on 27 October 1430 left a power vacuum in the Grand Duchy of Lithuania. Although Vytautas had been slated for coronation, the Polish nobility blocked the crown, leaving the throne contested. The Lithuanian nobles initially elected Švitrigaila, but his refusal to acknowledge fealty to the Polish King Jogaila—his own brother—ignited a series of territorial disputes in Podolia and Volhynia. This defiance prompted Švitrigaila to build an anti-Polish coalition, securing support from the Teutonic Knights, the Golden Horde, and various eastern dukes.
The conflict escalated into a wider struggle when Sigismund Kęstutaitis staged a coup in 1432, backed by Poland. This split the nation into two camps: Sigismund held the Lithuanian heartlands, while Švitrigaila maintained control over eastern territories like Smolensk, Kiev, and Vitebsk. To neutralize the Teutonic Knights' support for Švitrigaila, Poland orchestrated a Hussite invasion of Prussia in 1433. This 'beautiful ride' by Czech forces devastated Teutonic territories, effectively cutting the Order off from imperial aid and forcing them to sign the Truce of Łęczyca in December 1433.
The war reached its climax at the Battle of Wiłkomierz in September 1435. An estimated 30,000 soldiers clashed in a decisive engagement that saw Švitrigaila’s forces, led by Sigismund Korybut, soundly defeated by the Lithuanian-Polish army. The defeat crippled the Livonian branch of the Teutonic Knights and effectively ended the Order's ability to interfere in Polish-Lithuanian affairs. Although Sigismund Kęstutaitis emerged victorious, his rule was short-lived; he was assassinated in 1440. The succession dispute finally concluded when Casimir IV Jagiellon was accepted as the hereditary ruler, marking the end of the chaotic period that had threatened to dissolve the union between Poland and Lithuania.
Source: Lithuanian Civil War (1432–1438)
