It was a battle that determined the further fate of Eastern Europe and one of the greatest clashes of the European Middle Ages.
The Battle of Tannenberg (also known as the Battle of Grunwald), in which the army of the Teutonic Knights and the forces of the Polish-Lithuanian Union clashed, took place on July 15, 1410. The battle was the culmination of a century-long conflict between Poles and newly baptized Lithuanians against the Teutons, who had been relentlessly spreading eastward since the first half of the 13th century.
The Teutons, who were knights-monks, were originally called from the Holy Land to subdue the pagan Prussians. After completing the task, the order was expected to return to the Holy Land, but their ambitions kept them in the area. Almost two centuries later, the entire Teutonic Knights were ruled by almost the entire southern and eastern shores of the Baltic, and its ambitions extended to Lithuania, Poland, and Russia.
The decisive battle, which determined the further fate of Eastern Europe, took place in the lowlands between the villages of Grunwald and Tannenberg and was one of the greatest battles of the European Middle Ages. The exact number of soldiers is not known, but the numbers range from 16 to 39,000 on the Polish-Lithuanian side, and from 11 to 27,000 on the Teutonic side.
The army of the Polish-Lithuanian Union, assisted by Mongol and Russian troops, was led by Vladislav II. Jagelović, and the Teutonic Grand Master Ulrich von Jungingen. The conflicting sides found themselves facing each other at dawn, but although Jagelović had just formed his fighting ranks, the Teutons missed the opportunity and did not immediately launch an assault. The lull lasted until noon when Jagelović launched an attack. The fighting lasted all day with alternating success. It was only in the afternoon that Polish-Lithuanian numerical superiority prevailed, and a tactical mistake from the beginning of the battle proved fatal when the Teutons lost their infantry in a raid by the Mongol and Lithuanian light cavalry.
Many Teutonic Knights were killed by Lithuanian infantry made up of peasants eager for revenge for the burned villages and the slain and enslaved compatriots. Few Teutons were captured, and even fewer escaped, and the Grand Master of the Order himself was killed.
The war ended with the peace of Torun the following year, and marked the end of the spread of the Teutons to the east and the beginning of the decline of this knightly-religious order