According to the Croatian chronicler Thomas the Archdeacon, the reason for this abrupt departure was that the Hungarian steppe, although expansive, did not provide enough grass to feed the huge herds of horses the Mongols required for long campaigning.24 But Mongol politics had also taken a sharp turn: Ögödei Khan, Genghis’s third son and successor as supreme khan, died in late December 1241, and there was a momentary power vacuum in Mongolia.
