Genghis Khan's succession
When Genghis Khan was deciding who should succeed him he had trouble choosing between Tolui and Ögodei. Tolui had amazing military skills and was very successful as a general, but Genghis Khan chose Ögodei because Ögodei was more capable politically. Genghis Khan felt that Tolui would be too cautious to be an effective leader.
After Genghis Khan's death, Mongol nobles gathered together and elected Tolui as the new Khan, but Tolui rejected their decision and gave the Khanate to his brother, Ögodei, fulfilling his father's wishes. The Mongol nobles' moves were partly influenced by the tradition that the youngest son inherits his father's properties and partly because Tolui had the largest and most powerful army at the time.
Death and Legacy
According to the Secret History of the Mongols, Tolui sacrificed himself in order to cure Ögödei from a very severe illness during a campaign in China. The shamans had determined that the root of Ögödei's illness were China's spirits of the earth and the water, who were upset that their subjects had been driven away and their land devastated. Offering land, animals and people had only lead to an aggravation of Ögödeis illness, but when they offered to sacrifice a family member, Ögödei got better immediately. Tolui volunteered and died directly after consuming a cursed drink.
Perhaps more important than him was the role his family, the Toluids, had in shaping the destinies of the Mongol Empire. Through his Christian wife Sorghaghtani Beki, Tolui fathered M&, , Ariq Boke, and , and thus was the progenitor of the last of the great Khans, the Yuan Dynasty of China, and of the .
Rivalry between the Toluids and the sons of Ögedei and Jochi caused stagnation and infighting during the regency periods after the deaths of Ögedei and his son . However, it was a rivalry from among Tolui's own sons, Kublai and Ariq Boke, that fragmented the power of the empire and set the western khanates against each other in the early 1260s.