Köten forged an alliance with the Kievan Rus against the Mongols (also called Tatars) after a defeat in 1222. The Cuman–Kipchak confederation under Köten and a Rus army of 80,000 men under his son-in-law Mstislav the Bold fought a battle at the Kalka River (Kalchik, near Mariupol) against a Mongol contingent commanded by Jebe and Sübötäi. The Rus-Cuman army was routed and had to retreat on 31 May 1223. Köten was deposed from power in that year, but he remained leader of the Terteroba clan.