The years following 1260 saw the empire irrevocably split but also signaled the emergence of the two greatest achievements of the house of Chinggis, namely the Yiian dynasty of greater China and the 11-Khanid dynasty of greater Iran. In Iran the Mongol rulers eventually converted to Islam when Ghazan Khan acceded to the throne in 1295. Many have seen the reign of Ghazan Khan and his prime minister, the vizier Rashid al-Din, as the Il-Khans' golden age. This, however, has had more to do with the fact that the later historians were Muslim who preferred to award merit and praise to a fellow Muslim, especially a convert, than to "infidels." In fact, both Hiilegii and his son Abaqa presided over a culturally and economically prosperous period of Iranian history that was also relatively peaceful. Abu Sa'-Td, the last 11-Khan, died in 1235 without heir, and thereafter the line of Hiilegii effectively disappeared. Short-lived Mongol dynasties such as the Jalayrids in western Iran with their capital in Baghdad, the peasants' regime of the Sarbadars in the north of the country, the Persian Karts in Khorasan, and the Muzaffarids of Shiraz all appeared and prospered briefly, but by 1400 they had all fallen to a new storm from the East. This storm was led by Timurlane (1335-1405), another leader of a Turco-Mongol tribe.
In China, Qubilai Khan's successors never matched his achievements, though the dynasty continued for another 74 years. No more territorial expansion occurred, but the seeds that Qubilai Khan had planted prospered. After two disastrous attempted invasions of Japan, expansion in the east stopped. Just as the Mongol defeat by the Egyptian Mamluks at 'Ain Jalut in 1260 ended the myth of Mongol invincibility in the West, so the defeats by the Kamikaze winds and the Japanese in 1274 and 1281 marked the demise of their reputation in the East. But if the military superiority had come to an end, the legacy of Mongol rule lived on. The highly efficient communications network and the new roads emanating from the new capital Ta-tu (Beijing) ensured that China continued to thrive on international trade. When eventually the regime collapsed and the Ming, an ethnically Chinese dynasty, assumed control of the country, there was no attempt to deny the legitimacy of the Yiian for decades. Though it had been Mongol, the Yiian was accepted as an authentic Chinese dynasty. Zhu Yuanzhang proclaimed himself the new emperor in 1368, and the Ming dynasty he founded ruled until 1644.
It was the two empires founded by the Tolu id brothers, Hiilegii and Qubilai, that ensured the Mongols the lasting prestige and glory to match their martial reputation for indestructibility and ruthlessness. Both the Il-Khanate and the Yiian dynasty left an indelible mark on the culture and history of both Iran and China. In both states, which remained close for many decades, there was considerable assimilation between the rulers and the ruled.