The Decline of the Ilkhanate and the Mamluk Sultanate’s Eastern Frontier

In the period following the death of the last Mongol Ilkhan ruler Abū Saʿīd in 736/1335, the region east of the Mamluk Sultanate, from the Euphrates to the Oxus, was thrown into political upheaval. The Ilkhanate had been ruled by a dynastic line descended from Hülegü Khan, which, although witness to occasional succession disputes, had continued to provide undisputed leadership in the region since 656/1258. By the fourteenth century, dynastic succession had been settled in one branch of the Hülegüid family, through Hülegü’s son Abaqa, and Abaqa’s son Arghun. While this pattern helped to prevent the kind of succession crises that had occurred in the thirteenth century, it created a new problem of uncertainty when Abū Saʿīd Bahādur Khan died without an heir in 736/1335. The uncertainty of legitimate succession left several factions from among the state’s military elite scrambling to maintain their privileged positions. Various families of amirs and local notables entered into alliances with each other as well as with members of peripheral lines of the Ilkhanid royal family in an attempt to enhance their prestige and legitimize their claims to authority. In particular, the military governors in the western Ilkhanid provinces, in roughly the area from Baghdad north to Mosul, Diyarbakr, and Erzurum, which formed the traditional border zone with the Mamluk state, sought aid and recognition from the sultan in Cairo. Sultan al-Nāṣir Muḥammad welcomed such overtures as an opportunity to both secure the Mamluk northeast frontier, as well as extend the authority of the state beyond the Euphrates. For a brief period, it seemed as if this had been achieved, and the name of al-Nāṣir Muḥammad was read in the khuṭbah in the mosques of Baghdad, Mosul, and Diyarbakr. This article is an attempt to untangle the often confusing web of political networks and allegiances in this frontier zone and to analyze the factors that led to the recognition of Mamluk authority east of the Euphrates River, as well as the breakdown in relations and the eventual reversion to the status quo ante, with the Euphrates dividing the Mamluk domains and the lands which would continue to look to the legacy of the Ilkhanate as a model for its geographical and political orientation.