Battle of the Kalka River
The Battle of the Kalka River (, ) was fought between the Mongol Empire, whose armies were led by Jebe and Subutai the Valiant, and a coalition of several Rus' principalities, including Kiev and Halych, and the Cumans. They were under the joint command of Mstislav the Bold and Mstislav III of Kiev. The battle was fought on May 31, 1223 on the banks of the Kalka River in present-day Donetsk Oblast, Ukraine, and ended in a decisive Mongol victory.