Wikipedia
Temüge (1168 – 1246) was the youngest full-brother of Genghis Khan. As the youngest sibling, Temüge and his mother, by Mongol traditions, were allotted the most land and people by Genghis Khan during his coronation. Although he seems to have been the least warlike of the brothers, and was criticized by Genghis himself for being lazy and shiftless, Temüge proved himself to be a skilled politician and capable ruler, who, alongside his mother Hoelun, ruled the Mongol heartland in his eldest brothers' absence. He appears to have had intellectual leanings, first coming under the influence of the conquered Xia and Jin cultures and then taking an active interest in the other cultures encompassed in the vast Mongol empire.
After the death of his nephew Ögedei Khan, Temüge attempted to seize the throne for himself in 1246, an act which resulted in his execution.