‘Even when Jesus was small, the villagers realized there was something unusual about him,’ observes Catherine Nixey in the opening of her new book. She considers a couple of possible reasons for this, and then proposes: ‘Or perhaps it was because he killed people.’ That’s how she introduces the apocryphal Infancy Gospel of Thomas, which recounts Jesus’s murderous deeds and plays an important part in her book. Elsewhere in Heresy, a chapter starts: ‘The problem, as St Augustine knew well, was the vagina of the Virgin Mary.’ Hardly a hot topic for today’s theologians, Mary’s vagina, or ‘to be more precise her hymen’, was at one time an ‘issue of profound theological importance to Christianity’. 

Heresy is replete with bold stylistic heresies of this kind. Writing to provoke an audience seems to come naturally to Nixey. It’s what she does for a living, after all. An accomplished journalist, she tackles her subject with wit and verve – indeed, with considerable cheek – and an excellent command of mise en scène.

The book’s stated focus is the decades following the Roman Empire’s embrace of Christianity in the fourth century AD, yet there is much zigzagging across time and space. From pagan Greece to 19th-century America, from medieval China and India to mid-20th-century Iraq and Egypt, Heresy covers quite a bit of ground. The sprawling narrative is as enticing as it is disorienting – riskily so at times.

In February 313, an edict was passed in Milan that was to change world history in a way that few legal documents, before or after, ever would. It stated, reasonably enough, that ‘it was proper that the Christians and all others should have liberty to follow that mode of religion