On 9 April 1241 a Mongol column destroyed a Polish and German army under Duke Henry II the Pious of Silesia at Legnica. Henry was killed and his head paraded on a lance — a crushing defeat that shielded the flank of the main horde as it prepared to annihilate Hungary two days later.
The Battle of Legnica on 9 April 1241 was the northern half of the Mongols’ twin victories in Latin Europe. A flanking column shattered a Polish-German army under Henry II the Pious of Silesia, proving that western knighthood was as helpless against the Mongols as the Rus’ and the Hungarians.
The invasion of Europe in 1241 came in two prongs. While Batu and Subutai led the main horde into Hungary, a northern column under Baidar and Kadan ravaged Poland to protect the flank, sacking Kraków. Duke Henry II of Silesia assembled a mixed force of Polish and German knights — including small detachments of the Templars, Hospitallers, and Teutonic Knights — and gave battle near Legnica before the Bohemian army could reach him.
The Mongols used their standard tactics with deadly effect: a feigned flight drew the Christian knights into a disordered charge, after which the horse-archers wheeled, enveloped them, and cut them apart. Chronicles describe a smoke screen that blinded and confused the heavy cavalry.
Henry II the Pious was killed trying to escape, and the flower of Silesian and Polish chivalry fell with him; the military orders’ contingents were largely destroyed. A surviving Templar reported the disaster in a letter to the king of France.
The Mongols paraded Henry’s severed head on a lance before Legnica’s castle but did not besiege it. Their task — to shield the main army’s flank — was done, and the column rode south to rejoin Batu. Two days later the Hungarian army was destroyed at the Battle of Mohi, and for a few months it seemed all of Latin Europe lay open.