Abaqa's death in 1282 triggered a succession struggle between his son Arghun, supported by the Qara'unas, and his brother Tekuder, supported by the Chinggisid aristocracy. Tekuder was elected khan by the Chinggisids. Tekuder was the first Muslim ruler of the Ilkhanate but he made no active attempt to proselytize or convert his realm. However he did try to replace Mongol political traditions with Islamic ones, resulting in a loss of support from the army. Arghun used his religion against him by appealing to non-Muslims for support. When Tekuder realized this, he executed several of Arghun's supporters, and captured Arghun. Tekuder's foster son, Buaq, freed Arghun and overthrew Tekuder. Arghun was confirmed as Ilkhan by Kublai Khan in February 1286.

During Arghun's reign, he actively sought to combat Muslim influence, and fought against both the Mamluks and the Muslim Mongol emir Nawruz in Khorasan. To fund his campaigns, Arghun allowed his viziers Buqa and Sa'd-ud-dawla to centralize expenditures, but this was highly unpopular and caused his former supporters to turn against him. Both viziers were killed and Arghun was murdered in 1291.