Barnaby Rogerson’s new book has come along at precisely the right time. The House Divided, a vast history of the Sunni–Shia divide, is a balanced, sweeping, hugely ambitious work that delves into the long and tangled roots of the modern Middle East. Rogerson examines both what divides Sunni, followers of the ‘way’ of Muhammad, and Shia, devoted to Ali, the Prophet Muhammad’s son-in-law, and what binds them. It is also a study of geopolitics, history and how societies and empires rise and fall. Despite occasionally feeling chivvied along at the expense of important detail, the reader is left better informed about a large swathe of global history.

Following Muhammad’s death in 632, disputes rumbled on between two parties of his followers: Sunni and Shia. These tensions culminated in the death of Husayn ibn Ali, the grandson of the Prophet, at the Battle of Kerbala in 680 while fighting the forces of the Umayyad caliph Yazid I. After the battle, Rogerson writes, ‘In Mecca, the Kaaba was a burned-out ruin and in a neglected field at Kerbala the headless corpses of the murdered family of the prophet of God lay buried. It was as if the things of this earth had been won but in the process the kingdom of heaven had been forgotten.’ 

Rogerson doesn’t begin his account here, however. He takes the reader back to the start of Islam, before the split, to Muhammad’s early life in Mecca, where he dispensed wisdom among his family and followers. This didn’t relate to temporal power or worldly success, but rather to ‘how all should