In the mid 13th century the Mongols were still an immensely powerful military and political force, but like all empires, and empires by definition expand, the Mongols were running into the limits of their own expansion. After Leignitz, the Mongols would never come this far west again. That said they defeated an army that represented the best combat technology in the west at the time. The Mongol empire in the mid 13th century was one of the largest land empires in the history of the world reaching from Poland to Vietnam. The Khanate of the Golden Horde had captured most of Russia and wintered into the steppes of Romania and in the Don Valley. Subedei had a master plan that involved a diversionary invasion of two touman or 20,000 mounted Mongol warriors into Poland and Lithuania, while another ten touman would invade in a two-pronged attack. Batu would lead four touman into Transylvania, and Siban would take touman into the Carpathian Mountains from the north. If the Europeans responded with too much force, the northern and southern forces would join and encircle defending troops. It was a masterful plan that exceeded the planning one might expect from a force of 90% cavalry.
Batu preceded the invasion with a warning letter to King Bela of Hungary demanding surrender or total destruction. Bela pulled together a100,000 man strong Hungarian army that closed ranks and formed a laager or chain of wagons and cannons. The touman under Bela encircled the laager and used catapults and chemical weapons to turn the Hungarian lines into a death trap. 70,000 Hungarian troops perished and Bela had to cross the Adriatic.
Meanwhile the Mongols under Baidar and Kadan had left a scorched Earth from Lublin to Warsaw. Few opposed them and so their feint wasn’t working. So they split their forces to create a more inviting target, and it worked. Henry of Silesia began culling together an alliance to oppose Baidar and Kadan. King Wenceslas of Bohemia was putting together a force of 50,000 to join Henry’s 25,000 forces. So the Mongols opted to attack the smaller force before the two European armies united. Henry sat with 25,000 at Leignitz. It was April 1241.
The elite Mongol Magudai cavalry numbered 1,000 men. Mounted archers numbered 11,000. Heavy cavalry numbered 8,000. The Mongols had been taken from army different Mongol tribes and bands. But these were blooded warriors who had been fighting from childhood to this very day and had smashed one army after the next. The allies they faced were a mix of mercenaries, people who spoke many languages, and men with far less training under their belt, army craftsmen and farmers who only served while they were being paid. The Knights at arms under Henry numbered 8,000. Light cavalry numbered 3,000 and infantry number 14,000.
All of the Mongols were mounted, mobile or able to encircle and cover territory. Most of the allies were infantry, encumbered by armor, unable to form up and maneuver as quickly.
On a field of battle the Hungarians led with two formations of knights, in good order. In the rear was arrayed the infantry.
Facing them was a huge formation of heavy Mongol cavalry. They stood in formation hundreds of meters away, quiet. Meantime the Mongol Magudai cavalry attacked the first Hungarian cavalry that was so poorly trained, they fled immediately, crashing into the Hungarian cavalry behind them. The Hungarian cavalry and commanders in the second line rallied and redirected the fleeing first line. The Magudai then turned and fled, and the rallied Hungarian cavalry and the reinforcements behind them took the bait and pursued the Mongols, believing that they were routing the Mongols.
The Mongols were of course faking the rout and sure enough the Hungarian heavy cavalry rode into a trap. In front of them their progress was blocked by the Mongol heavy cavalry. The Magudai cavalry then return and encircled the Hungarians. The Hungarians were surrounded suddenly. The Mongols lighted fires from combustibles they planted earlier on the battle field specifically to create a smoke screen. Encircled and under constant Mongol archery fire from front, from the back and from the sides, and now blinded by smoke, the Hungarians were slaughtered. When the remainders fled back out of the cloud towards the Hungarian lines the infantry followed suit and ran. They were all killed and another twenty thousands people on the Oder river were murdered just as punishment.
The Mongols cut ears off of all the Hungarian dead to provide a tally for the Commanders. It is aid that Mongols carried sacks of ears back to the Khanate. The Europeans never clashed with the Mongols in a set piece battle this large, but it was not because the Mongols were worried. Ghengis Khan had died. But the political fight over his succession split the empire. It was the Mamluk Muslims in Egypt who finally delivered the Mongols their last defeat.