Battle of Tannenburg

The Battle of Tannenberg, also known as the Battle of Grunwald, was fought on July 15, 1410, between the allied forces of the Kingdom of Poland and the Grand Duchy of Lithuania and the Teutonic Knights, a German crusading military order. The conflict arose from long-standing disputes over territory and the order's domination of the Baltic coast, intensified by the Polish-Lithuanian union under King Wladyslaw II Jagiello.

In one of the largest battles of medieval Europe, the combined Polish-Lithuanian army, commanded by Jagiello alongside Grand Duke Vytautas, decisively defeated the Teutonic Knights. The order's Grand Master, Ulrich von Jungingen, was killed, and much of its leadership was destroyed, breaking the military power that the Knights had long projected across the region.

Despite the scale of the triumph, the victory was not fully exploited. The Knights' capital at Marienburg withstood a subsequent siege, and the Peace of Thorn signed in 1411 left the order largely intact, with Poland failing to secure access to the Baltic Sea. Nonetheless, the battle marked the beginning of the Teutonic Order's long decline and a lasting symbol of Polish and Lithuanian unity.