Batu Khan (; , , , ; c. 1207–1255), also known as Sain Khan (, Сайн хаан) and Tsar Batu, was a Mongol ruler and founder of the Golden Horde, division 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, 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.