Valens helped Sasan back up onto the track.

‘The levee is clear.’ Narses had returned. ‘The old eunuch did well. But we must hurry.’

*

When they crossed the deserted levee, Valens thought about turning the Persian horses free, stampeding them. But that would make a noise. There would be other Sassanids nearby in the watchtowers, and it would give them proof that the Romans had slipped past. If the hunters took Barbad alive, Valens doubted the eunuch would tell them anything.

Narses navigated them to a spit of firm ground running into the fens from the north-east. They took it at a walk. When they reached the plain, they moved to a trot, then a gentle canter.

Sunrise found them still in the saddle. Its low, slanting light threw their shadows far out across the plain. Everyone was relieved that the Walls of Alexander were out of sight over the horizon.

The Steppe here rolled like a sea in a gentle swell. It was cut by little watercourses running off to the west. By the third hour of daylight the horses were stumbling with weariness, and roped in sweat. They stopped and watered them at a stream. Although no one had slept in the night, Valens set a watch, and Decimus chivvied those not on that duty to see to the horses.

Despite the cold, men and animals were glad to get into the rivulet and have its bracing water wash away the foul and clinging black mud of the swamp. The men put on clean tunics from their saddlebags, and rubbed the horses dry. They were down to the last of their rations – some hard tack and a morsel of bacon – and there was no food for their mounts. But the autumn rains had revived the grass, and they hobbled the horses and let them graze. Supplies should not be a problem. The Steppe was nothing but thousands of miles of grass, and the men could live off what they caught hunting.

Young Prince Sasan did not want to eat. He was desolate at the loss of the old eunuch. Clemens sat close to him, and tried to offer consolation in Greek. There was a tenderness about his actions. The severe, time-worn face – so very like a sculpture of a senator from the stern time of the ancient republic – bent over that of the boy, showing the concern of a father.

All Clemens’s efforts were in vain. The boy continued to sob.

Narses, resplendent in a tunic embroidered with the heraldry of the Suren clan, went over. He pulled the child to his feet. Gripping Sasan’s shoulders, Narses spoke to him sharply in Persian. The boy wiped the tears from his eyes with his knuckles, took several deep and shuddering breaths, and stopped crying. Narses passed him a biscuit, and he ate.

‘What did you say?’ Valens asked.