Dr Toby Matthiesen is Senior Lecturer in Global Religious Studies at the University of Bristol. 

In this new book Dr Matthiesen looks at the way, at this death, the followers of the Prophet Muhammad disagreed on who should succeed him. This argument started in AD632. This book traces the history of the split through history and shines a light on the modern world. Was the invasion of Iraq a good idea?

The Caliph and the Imam is published by Oxford University Press.