In the Ilkhanate, the peak of Mongol rule came under Ghazan. With his death in 1304, the Ilkhanate entered an unstable period. Princes in the royal family fought for control. Ghazan had picked his brother Kharbanda (c. 1280-1316) as his successor, and Kharbanda killed several relatives he considered rivals. He then took power under the name Oljeitu, which means “fortunate.”
Around this time, the four branches of the Mongol empire entered a brief period of cooperation. As Oljeitu noted in a letter to the king of France (cited by J. A. Boyle in The Cambridge History of Iran), “. . . protected by Heaven, all of us, elder and younger brothers, reached a mutual agreement. . . .” This relationship, however, did not mean the Great Khan was once again ruling over a united empire. In practice, the four khanates continued to go their separate ways, grapple with their own problems, and sometimes compete for land and power.
Oljeitu, like his brother, hoped to continue fighting the
Mamluks of Egypt. He also hoped to receive help from the Christian rulers of Europe. But his more immediate problem was in Gilan, an area near the Caspian Sea. During fierce fighting there, the Mongols won several battles before the local residents managed a major victory. Eventually, Gilan was conquered, but at a very high cost. By 1308, Oljeitu learned that the European kings were not eager to help him battle the Mamluks. In 1312, he launched his only attack against the Ilkhanate’s long-time enemy. A month-long siege in the Mamluks’ Syrian lands failed, and Oljeitu retreated. The Mongols would never again invade Mamluk territory.