A bitter family feud reshaped medieval Europe through shifting alliances and secret betrayals
The Lithuanian Civil War of 1389 to 1392 was a power struggle between cousins Jogaila and Vytautas. As they fought for control of the largest state in Europe, both men repeatedly courted the Teutonic Knights, their shared enemy, only to abandon those alliances when political necessity demanded a new direction.
The conflict originated from the death of Algirdas in 1377, which shattered the peaceful co-rule established by his brother Kęstutis. Jogaila, who became King of Poland in 1386, installed his brother Skirgaila to govern Lithuania, alienating the local nobility and his cousin Vytautas. Vytautas, seeking to reclaim his influence, twice allied with the Teutonic Knights, promising them Samogitian territory in exchange for military support. These alliances were fraught with mistrust; the Knights demanded high-ranking hostages, including Vytautas’ wife and siblings, to ensure his compliance.
The war featured brutal sieges, including a five-week assault on Vilnius in 1390 that destroyed the Crooked Castle. Despite the involvement of international crusaders—including the future King Henry IV of England—neither side could secure a decisive victory. The landscape was devastated, and Polish nobles grew increasingly frustrated with the drain on resources caused by Jogaila’s preoccupation with Lithuanian affairs. By 1392, the stalemate forced a diplomatic pivot.
Jogaila proposed a compromise, offering Vytautas de facto control of the Grand Duchy. In a masterstroke of deception, Vytautas accepted the deal while inviting his former Teutonic allies to a feast at Ritterswerder Castle, where he promptly took them prisoner and destroyed their nearby fortifications. The resulting Ostrów Agreement of 1392 ended the civil war, establishing a power-sharing arrangement that allowed the cousins to remain at peace for decades. This stability eventually enabled their joint victory against the Teutonic Order at the Battle of Grunwald in 1410.
Source: Lithuanian Civil War (1389–1392)
