He is the author of Parable and Politics in Early Islamic History: The Rashidun Caliphs (2010) and Reinterpreting Islamic Historiography: Harun al-Rashid and the Narrative of the Abbasid Caliphate ...

IS militants paraded through Raqqa after the "caliphate ... the Abbasid Caliph al-Mansour chose Raqqa to serve as a second capital after Baghdad, and to help him defend north-eastern Syria ...