Today Christianity is the largest religion in the world, its influence felt in every corner of the globe. But where did this religion come from? How did it take shape and formulate its beliefs? This enthralling book takes us back to the beginnings, setting us in the world of the Roman Empire and assessing the dominant philosophies of the time. How was the New Testament written and determined? How, after the first century AD, did Christianity set out on the road to an intellectually coherent account of its faith? How did it relate to the other main religion that grew up at the same time - Gnosticism. In The Crucible of Christianity we see the battlelines drawn and understand how notions of orthodoxy and heresy emerged. We meet the key thinkers who forged Christianity out of the crucible of dispute and conflict.