How did Genghis Khan divide his empire among his four sons?

During his lifetime, Genghis Khan divided his empire among his four sons into ulus, which represented supremacy over specific tribes and territories rather than strictly defined borders. This division followed nomadic traditions where sons were granted shares of the inheritance as they reached manhood, with the youngest son remaining as the "guardian of the hearth and fire" to receive the residual heritage.12

The distribution was as follows:

• Jöchi (eldest son): Received the lands from the Yenisey River and the Aral Sea westward, encompassing southwest Siberia and west Turkistan, an area that later became the Golden Horde.12
• Chagatai (second son): Received Kashgaria (southern Xinjiang) and most of Mavrannakhar, the territory between the Amu Darya and the Syr Darya.12
• Ögödei (third son): Received western Mongolia and the region of Tarbagatai in northwestern Xinjiang.12
• Tolui (youngest son): Inherited the ancient Mongol homeland in eastern Mongolia.12

This division was intended to maintain the empire as the heirloom of the imperial clan, though it ultimately contributed to the eventual fragmentation of the Mongol state.1