Batu Khan (; , , ; c. 1207–1255) was a Mongol ruler and founder of the Ulus of Jochi (or Golden Horde), the sub-khanate of the Mongol Empire. Batu was a son of Jochi and grandson of Genghis Khan. His ulus was the chief state of the Golden Horde (or Kipchak Khanate), which ruled Rus, Volga Bulgaria, Cumania, and the Caucasus for around 250 years, after also destroying the armies of Poland and Hungary. "Batu" or "Bat" literally means "firm" in the Mongolian language. After the deaths of Genghis Khan's sons, he became the most respected prince called agha (elder brother) in the Mongol Empire.