Karen Armstrong argues against the notion that religion is the major cause of war. The former nun tells Tom Sutcliffe that faith is as likely to produce pacifists and peace-builders as medieval crusaders and modern-day jihadists. But Justin Marozzi charts the violent history of Baghdad and asks what role religion had to play there. The philosopher Christopher Coker explores how warfare dominates our history, and argues that war, like religion, is central to the human condition. Producer: Katy Hickman.