The period between the conversion of Constantine the Great in AD 312 and the accession of Theodosius II in AD 408 witnessed one of the most dramatic changes in world history. The Roman Empire, the superpower of the ancient Mediterranean world, was Christianised. At the start of the period, no more than 10 per cent of its population was Christian; by the end, this may have been nearing 90 per cent. As Catherine Nixey’s long-awaited book demonstrates, these changes did not come about quietly but were effected by force. Non-Christians were systematically persecuted – their temples ransacked, their statues smashed, their bodies beaten and burned. Hers is a tale written from the perspective of the losers, a salutary reminder of the darker side of the rise of Christianity.