Mongol Scouts Rout the Rus Princes at the Kalka River

In the late spring of 1223, two of Genghis Khan's foremost commanders, Jebe and Subutai, drew a coalition of Eastern European rulers onto an open steppe battlefield. The expedition had begun years earlier during the Mongol operations against the Khwarezmian Empire. After pursuing the fallen shah, the two generals obtained imperial permission to undertake a reconnaissance in force through the Caucasus. Moving through Persian Iraq and Azerbaijan, their mounted forces defeated local kingdoms, negotiated difficult mountain crossings, and routed an alliance of northern Caucasian peoples and Cumans before pressing westward toward the Black Sea steppes.

The Cuman leader Koten fled to his son-in-law, Prince Mstislav Mstislavich of Galicia, warning that the arriving horsemen would soon threaten the regional Slavic realms. Although the Cumans had fought the princes for decades, their appeal persuaded several rulers from Kievan Rus to form an alliance. Rulers including Mstislav of Galicia, Mstislav III of Kiev, and Prince Mstislav of Chernigov gathered their contingents to confront the unexpected threat. The coalition was broad, but it suffered from the absence of a unified supreme commander, allowing individual princes to act independently.