Mongolian peoples established kingdoms in north China in the 4, and 10th centuries. Mongol organization declined after his death. His grandson, Chinggis Khan, originally named Temujin, was a member of one of the clans disputing Mongol leadership at the end of the twelfth century. Temujin gained strength among the Mongols through alliances with more powerful groups. After defeating his rivals, he was elected supreme ruler (khagan) of all Mongol tribes in 1206.