The Battle of Mohi (11 April 1241), also known as Battle of the Saj River or Battle of the Tisza River, was the main battle between the Mongol Empire and the Kingdom of Hungary during the Mongol invasion of Europe. It took place at Muhi (then Mohi), southwest of the Saj River.

Batu Khan (c. 1205 – 1255), also known as Tsar Batu in Russian historiography, was a Mongol ruler and founder of the Golden Horde, a constituent of the Mongol Empire. Batu was a son of Jochi, thus a grandson of Genghis Khan. His ulus ruled over the Kievan Rus', Volga Bulgaria, Cumania, and the Caucasus for around 250 years.