How did the division among Genghis Khan’s sons contribute to the breakup of the Mongol empire?

The division of the Mongol Empire among Genghis Khan’s sons was a primary factor in its eventual fragmentation. Genghis Khan partitioned his empire into ulus—territories governed by his four sons—which established a decentralized structure that prioritized the interests of individual branches of the imperial clan over a unified state.1

This division contributed to the empire's breakup in several ways:

• Lack of Centralized Administration: The empire functioned as a vast agglomeration of territories held together by military force rather than a cohesive state. The absence of a unified financial or administrative system allowed the various appanages to operate with a high degree of independence.1
• Cultural Divergence: As the separate segments of the empire settled, they adopted the diverse cultural and religious identities of their subject populations. The Golden Horde became Turkic and Muslim, the Il-Khans adopted Persian and Islamic traditions, and the Great Khans in China became Sinicized.23
• Succession Disputes: The system of choosing a Great Khan led to frequent internal conflict. Rivalries between the houses of Jöchi, Chagatai, Ögödei, and Tolui undermined political unity, eventually leading the separate khanates to pursue their own paths after the death of Kublai Khan.23