The project focuses on the dialogical engagement of the West Syrian Maphrian, Gregory Barhebraeus (1226-1286CE), with Islamic philosophy; an engagement which emerged from his study of philosophical thinkers coming from the Avicennan tradition. Barhebraeus’ apparent rejection of Aristotelian metaphysics in the discourse about God, was based on the affirmation that scholastic theology had become an immanent discourse predicated on the Aristotelian categories of existence. His encounter with the philosophical tradition of the other presents a historical model of inter-religious dialogue, between the Syriac Christian tradition and that of the post-Avicennan thinkers of the Islamic East. The research focus is on the sphere of Barhebraeus’ interaction with this tradition, through his visits to the extensive library of Marāgha in Persian Azerbaijan, established by Naṣīr al-Dīn al-Ṭūsī (1201-1274CE) under the Mongol patronage of the Il-Khans. I will explore to what extent Barhebraeus was influenced by debates internal to the post-Avicennan tradition, particularly through the contribution of al-Ṭūsī and his defence of Ibn Sīnā (980-1037CE).