Because atheism’s ancient history has largely gone unwritten, however, Whitmarsh suggests that it is also absent from both sides of the current monotheist/atheist debate. While atheists depict religion as something from an earlier, more primitive stage of human development, the idea of religious universalism is also built partly on the notion that early societies were religious by nature because to believe in god is an inherent, “default setting” for humans.

Neither perspective is true, Whitmarsh suggests: “Believers talk about atheism as if it’s a pathology of a particularly odd phase of modern Western culture that will pass, but if you ask someone to think hard, clearly people also thought this way in antiquity.”

His book surveys one thousand years of ancient history to prove the point, teasing out the various forms of disbelief expressed by philosophical movements, writers and public figures.

These were made possible in particular by the fundamental diversity of polytheistic Greek societies. Between 650 and 323 BCE, Greece had an estimated 1,200 separate city states, each with its own customs, traditions and governance. Religion expressed this variety, as a matter of private cults, village rituals and city festivals dedicated to numerous divine entities.