How was Genghis Khan’s empire divided among his sons?

Genghis Khan divided his empire among his four sons into ulus, which denoted supremacy over specific groups of tribes rather than strictly defined territories. This division followed nomadic traditions where sons received their 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, an area that later became the Golden Horde.21
• Chagatai (second son): Received the territory of Khara-Khitai, including Kashgaria and most of Mavrannakhar.21
• Ögödei (third son): Received western Mongolia and the region of Tarbagatai.21
• Tolui (youngest son): Inherited the ancient Mongol homeland in eastern Mongolia and adjacent parts of northern China.21

While these divisions were established during Genghis Khan's lifetime, the empire was considered the collective heirloom of the imperial clan, and a great khan was initially recognized by all branches to maintain a degree of unity.1