‘Surely not,’ Valens said. ‘Your Emperor ordered you to lay down arms. The fault lies with Valerian, not with you.’

‘Maybe so, but I am too old to move. Besides, I have married a Persian woman. Now I have a son and a daughter. The Persians value our skills. We are paid to build roads and dams and bridges, like the one here.’

‘They work us like slaves,’ the younger man said.

The older one smiled. ‘The taxes are lower here.’

‘Your new religion has taken your courage,’ the younger man snapped.

‘Mind what you say, boy.’ The older man exhaled noisily. ‘But yes, I have come to see the light.’

‘The light?’ Valens asked.

‘No harm here in bearing witness to my faith. It will not bring the pincers and the claws, will not see me burnt or mauled in the arena, as it would at home. For all the Persian priests talk of kindling sacred fires in conquered temples, Shapur tolerates all creeds. Jews, Manicheans, followers of the Olympian gods, all can practice their own rites. No harm in admitting that I have become a Christian.’

Valens and Aulus leant back, as if proximity might bring contagion.

Chapter 22

CHAPTER 22

The Southern Shores of the Caspian Sea

‘THE SEA! THE SEA!’

There, spread out below them, was the Caspian. Its waters glittered in the sunshine of the autumn afternoon. They extended further than the eye could see.

The men laughed and yelled and hugged each other. Thalassa! Thalassa! They capered like children, and shouted like the ten thousand of Xenophon at the end of their long march out of Persia.

It was an achievement to have come so far, yet Valens thought the exuberance misplaced. Xenophon’s men had escaped the lands of the Persian king. The ten thousand had reached the Black Sea. Its shores were studded with Greek cities. From any of them a man could take a boat, and sail back to Byzantium in a matter of days. Nowadays there were Roman garrisons around much of its coasts. The Caspian was an altogether different sea. It offered no succour and no passage back to civilisation. In the old days it had been believed to be a gulf opening off the northern ocean, and there was a story that an underground waterway linked the Caspian to Lake Maeotis, and thus to the Black Sea. They were no more than travellers’ tales. Even had they been true, neither would have provided an easy voyage home. The men with Valens had not escaped. They were deeper in enemy territory than ever, and their main dangers still lay ahead.

‘Mount up.’ Valens thought they should get down to the shore and find a campsite before dusk.

They rode down in a mood of easy congeniality.

‘Did you know,’ Clemens said, ‘there are islands out there full of gold? It is only the indolence of the Persians that leaves them unmined.’