The Battle of Tannenberg or Grunwald was fought between the Teutonic Knights of the Cross and a Polish Lithuanian alliance. The Teutons were outnumbered but better armored. The battle had many close moments, but in the end the senior command of the Teutonic knights were all killed and some 14,000 Teutonic troops surrendered in a complete defeat. It marked the beginning of the end of the Teutonic Knights’ grand “March to the East” to “Christianize” what were often already Christian peoples.
From Battles of the Crusades: