He kept his promise, and told me what I had seen that first night by the standing stone. I believe, had he told me to, I would even have dismissed it as a dream. As time went on, the memory had grown blurred and fainter, until I had begun to think it might have been a dream fostered by cold and hunger and some dim recollection of the faded picture on the Roman chest in my room at Maridunum, the kneeling bull and the man with a knife under an arch studded with stars. But when Ambrosius talked about it, I knew I had seen more than was in the painting. I had seen the soldiers’ god, the Word, the Light, the Good Shepherd, the mediator between the one God and man. I had seen Mithras, who had come out of Asia a thousand years ago. He had been born, Ambrosius told me, in a cave at midwinter, while shepherds watched and a star shone; he was born of earth and light, and sprang from the rock with a torch in his left hand and a knife in his right. He killed the bull to bring life and fertility to the earth with its shed blood, and then, after his last meal of bread and wine, he was called up to heaven. He was the god of strength and gentleness, of courage and self-restraint. “The soldiers’ god,” said Ambrosius again. “And that is why we have re-established his worship here—to make, as the Roman armies did, some common meeting-ground for the chiefs and petty kings of all tongues and persuasions who fight with us. About his worship I can’t tell you, because it is forbidden, but you will have gathered that on that first night I and my officers had met for a ceremony of worship, and your talk about bread and wine and bull-slaying sounded very much as if you had seen more of our ceremony than we are even allowed to speak about. You will know it all one day, perhaps. Till then, be warned, and if you are asked about your vision, remember that it was only a dream. You understand?”

I nodded, but with my mind filled, suddenly, with only one thing he had said. I thought of my mother and the Christian priests, of Galapas and the well of Myrddin, of things seen in the water and heard in the wind. “You want me to be an initiate of Mithras?”

“A man takes power where it is offered,” he said again. “You have told me you don’t know what god has his hand over you; perhaps Mithras was the god in whose path you put yourself, and who brought you to me. We shall see. Meanwhile, he is still the god of armies, and we shall need his help . . . Now bring the harp, if you will, and sing to me.”