Today in the Middle Ages: May 31, 1223

Genghis Khan's warriors first engaged the Rus on May 31, 1223 in the Battle of the Kalka River.

The Mongol incursion was intended as a reconnaissance in force rather than a conquest, but still included two of Genghis Khan's finest commanders and 30,000 troops. Their agile light cavalry and long-range bows gave them an advantage over the Slavic warriors, who were routed at the river.