Rashid-al-Din Hamadani
According to Rashid-al-Din Hamadani, Berke led a third campaign in 1238 which inflicted final defeat on the Cumans-Kipchaks. Ukrainian sources claim that it was Batu Khan that defeated Köten on the Astrakhan steppes. Afterwards, Köten led 40,000 "huts" (families, around 70-80,000 people) to Hungary fleeing the Mongols.