This week Neil MacGregor is exploring how many of the great religions, less than 2000 years ago, began creating sophisticated new images to aid prayer and focus devotion. Many of the artistic conventions created then are still with us. In today's programme Neil MacGregor introduces us to one of the earliest known images of the face of Christ. This life sized face is part of a much bigger mosaic. It was made somewhere around the year 350 and was found not in a church but on the floor of a Roman villa in Dorset. What does this astonishing survival say about the state of Christianity at this time and what sort of Christ was imagined in Roman Britain? The historians Dame Averil Cameron and Eamon Duffy help paint the picture. Producer: Anthony Denselow