Forces from a division of the Mongol Empire called the Golden Horde, led by Batu Khan, a grandson of Genghis Khan, began attacking Europe in 1223, starting with the Cumans, Volga Bulgaria and Kievan Rus. They destroyed many cities including Kiev, Vladimir and Moscow in the process. They originally planned to continue all the way to the shores of the "Great Sea" (Atlantic Ocean). However, upon learning of the death of Ögedei Khan (third son of Genghis Khan, uncle of Batu Khan) in 1241 they returned eastwards to their steppe homelands. This, it could be argued, saved the rest of Europe from suffering the catastrophes that befell the armies and towns of the Kingdom of Poland and the Kingdom of Hungary, although over-stretched lines of communication and the lack of vast open tracts of pasture land might well have proved the undoing of such a venture. However, Turco-Mongol occupation of much of Eastern Europe then persisted for centuries.