After completing their destruction of the Khwarizm Empire, the Mongol generals, Jebe and Subuta, rampaged north, through the Caucasus, subduing Georgia and Black Sea tribes en route. The tribal union of Polovtsy sought the aid of the principalities of Kievan Rus in defending their territories. Finding themselves under attack, the Mongols used a favourite tactic, feigning retreat to stretch the enemy lines. They turned to face the Rus forces at the Kalka River, north of the Sea of Azov. The Polovtsy forces broke under their charge, and the agile Mongol cavalry soon split and enveloped their enemy, slaughtering them en masse. Only two contingents escaped, under Mstislav of Galich, who broke through and fled to safety, and Mstislav of Kiev, who was soon cornered, captured and executed. The Mongols did not exploit their victory immediately, turning back to rendezvous with Genghis Khan. In 1237, Subutai returned to complete the conquest of Rus.
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