We speak with Dr Bojana Radovanović on the Bogomils, a widespread Christian ‘heresy’ – dualist, demiurgic, docetist, ascetic, and esoterically-structured – arising in the tenth-century Balkans and spreading into such unlikely places as Constantinople and even the monastery of Mt Athos. We discuss the who, what, and when of Bogomilism, animadvert as to the why, and even speculate intriguingly on the how.