The Thirteen Years' War was fought between the Kingdom of Poland and the Teutonic Order from 1454 to 1466, primarily over issues of sovereignty and territorial boundaries. The conflict arose when local Polish nobility sought protection against the Teutonic Order, leading to an insurrection in Pomerelia. Over the years, the war saw numerous battles, shifting alliances, and changing fortunes. The war was heavily influenced by the support of various European powers, including the Kingdom of Poland's alliances with the Kingdom of Hungary and the Grand Duchy of Lithuania. Eventually, the prolonged warfare impacted both the Polish economy and the military strength of the Teutonic Knights.%0A%0A The Second Treaty of Thorn was a significant diplomatic resolution to this long-standing conflict. Negotiated after the decisive Battle of Tannenberg in 1466, the treaty returned Pomerelia to Poland, while the Teutonic Order retained control over the remaining territories, although as a vassal state. This change in status meant that the Order was obliged to acknowledge Polish suzerainty. The treaty not only ended hostilities but also reshaped borders and influenced the political landscape for years to come. It was a turning point that saw the dissolution of the Teutonic Order's political power in the region and paved the way for future Polish expansion and the eventual rise of the Polish-Lithuanian Commonwealth.