The Thirteen Years' War (1454-1466) was a conflict between the Teutonic Knights and the Kingdom of Poland, along with its ally, the Grand Duchy of Lithuania. The war began when the cities of Gdańsk and Pomerania sought to break free from the control of the Teutonic Order, leading to a broader struggle for power in the region. The war concluded with the Second Peace of Thorn in 1466, which resulted in significant territorial losses for the Teutonic Knights. As a result, the Order retained only a small portion of its territory, while the rest was divided between Poland and the newly established Prussian Duchy.