The Polish-Lithuanian-Teutonic War or Great War occurred between 1409 and 1411, pitting the allied Kingdom of Poland and Grand Duchy of Lithuania against the Teutonic Knights. Inspired by the local Samogitian uprising, the war began by Teutonic invasion of Poland in August 1409. As neither side was ready for a full-scale war, Wenceslaus IV of Bohemia brokered a nine-month truce. After the truce expired in June 1410, the military-religious monks were decisively defeated in the Battle of Grunwald , one of the largest battles in medieval Europe. Most of the Teutonic leadership was killed or taken prisoner. While defeated, the Teutonic Knights withstood the siege on their capital in Marienburg  and suffered only minimal territorial losses in the Peace of Thorn . Territorial disputes lasted until the Peace of Melno of 1422. However, the Knights never recovered their former power and the financial burden of war reparations caused internal conflicts and economic decline in their lands. The war shifted the balance of power in Eastern Europe and marked the rise of the Polish-Lithuanian union as the dominant power in the region.. What caused the nine month long truce between Teutonic and Poland?