On 4 March 1238, on the frozen Sit River, a Mongol column caught and destroyed the army Grand Prince Yuri II of Vladimir had gathered to fight back. Yuri was killed, and organised resistance in northern Rus’ collapsed.
The Battle of the Sit River on 4 March 1238 destroyed the last field army of northern Rus’ and killed Grand Prince Yuri II of Vladimir, sealing the Mongol conquest of the north-east.
After Vladimir fell, Yuri II gathered what forces he could on the Sit River, hoping to unite the contingents of his kinsmen before striking back. But the Mongols moved faster than he expected, and a column under Burundai located his camp before his army was ready.
On 4 March 1238 the Mongols surprised and surrounded the Rus’ on the frozen river. Caught unprepared, Yuri’s army was routed and cut to pieces, and the grand prince himself was killed in the slaughter.
The defeat left the principalities of the north-east without a leader or an army.
The Mongols pressed on toward Novgorod but turned back short of the great trading city as the spring thaw made the marshy roads impassable, sparing it the fate of Vladimir. Batu withdrew to the southern steppe to rest his horses and prepare the next phase — the destruction of southern Rus’ and the invasion of Europe.