Caliph Al-Mu‘tasim’s Expedition against Amorion in 838 AD: The Chronology Reconsidered

This research offers a detailed reconstruction of one of the most famous episodes of Byzantine-Arab relations in the ninth century, the victorious campaign of the Abbasid army led by Caliph al-Mu‘tasim deep into the territory of Byzantium in 838 AD, which ended with the defeat of the army of Emperor Theophilos and the destruction of two most important fortresses in Asia Minor, Ankyra and Amorion, the native place of the ruling dynasty. The accounts of the circumstances and the route of this expedition kept by Arab, Syrian, and Greek sources make it possible to build a detailed chronological map of this military campaign with the use of new methodology created for the project of the comprehensive database of events of Byzantine history. The bringing together chronological and topographic indications of all available sources made it possible not only to make a complete reconstruction of the military operations, but also to revise the date of one of the most important events in the ninth-century history of Byzantium, the battle of Anzen at Dazimon plain, when the Arab-Turkic-Armenian army commanded by Afshin inflicted a crushing defeat on the Byzantine army of Emperor Theophilus, which included the Persian detachments of the ex-Khurramites of Babek. Taking the data in possession into account, there are reasons to date the battle to July 4th, 838 AD. It is proposed to correlate the previously accepted date indicated by at-Tabari, July 22nd, with another key event of the 838 campaign, the destruction of Ankyra. In addition, a comprehensive analysis of the sources makes it possible to clarify the chronology and circumstances of the fall of Amorion, which surrender to the Arabs was resulted by an ethno-religious conflict.