He sits on his jewelled throne on the Horn of Africa in the maps of the sixteenth century. He can see his whole empire reflected in a mirror outside his palace. He carries three crosses into battle and each cross is guarded by one hundred thousand men. He was with St Thomas in the third century when he set up a Christian church in India. He came like a thunderbolt out of the far East eight centuries later, to rescue the crusaders clinging on to Jerusalem...