The Persian soldiers had not been overtly hostile, but they were not forthcoming. This morning they had watched as the heavy load of the wagon was carried into the storerooms. None had offered to help. Likewise they had given no help in bedding down the horses, had seemed happy to show the arrivals to the worst rooms in the barracks, and had kept apart when they ate. Narses said that they were resentful that these foreign mercenaries would be free to leave this dismal fortress in a few days.

‘It was a stroke of luck, that old man this morning,’ Iudex said.

It was a strange phrase to describe what they had seen, but it was true.

They had all been worried about the man they had seen urging his tired dromedary up towards the castle. The wagoneer had confirmed their suspicion that he was a messenger of the King. It would have been too cruel of fate if they had arrived on the same day as Shapur’s order to kill Prince Sasan.

So it was with relief that they had watched an elderly Persian nobleman dragged down the steps out of the tower. His public execution in the courtyard had been nothing worse than one saw in the Colosseum. First the torturers had sliced off his ears, then his nose. They had amputated his hands and gouged out his eyes. By the time they had decapitated him, he appeared to be already dead.

‘It was fortunate for us, but a pity for the old nobleman,’ Iudex added. ‘I would not have you think that I am inhumane.’

‘I thought you followers of Mani were like Christians, and believed taking a life was a terrible sin,’ Narses said. ‘Yet you were happy enough to kill the tent-dwellers, and it was you that slaughtered out of hand the brother of Lucia’s husband.’

Iudex tipped his bald head to one side, as if considering how much it was prudent to divulge.

‘I cannot think your prophet will do well at the court of the King of Kings,’ Narses said. ‘Imagine instructing Shapur to kill no one, not to touch meat and abstain from sex, let alone embrace poverty?’

‘When I was in Ctesiphon, in the palace of the Sassanid, I saw that Shapur was a man of violence, a slave to his appetites. It will end badly for Mani,’ Iudex said.

‘What were you doing at the Persian court?’ Valens tried to keep the sudden suspicion out of his voice.

‘The things that are done by a frumentarius,’ Iudex replied.

‘You have never mentioned this.’

‘It was a couple of years ago. We have all done things that are best left unsaid.’

‘Was it there you met this Mani?’ Valens asked.

‘It was Mani who put my feet on the road to liberation. He taught me to release my spirit-twin. Since then I have voyaged widely, learnt many things in the other world. Now the pupil has surpassed the teacher.’