Yet some nagging doubt lurked in the dark corners of Valens’s thoughts. So many bad things had dogged their steps: the bandits, the dust storm, the tent-dwellers. Of course, he had brought the last down on their heads. Unless you believed in magic, and Valens did not, the storm was just chance. But the more he considered them, the bandits were different. In the Greek novels he had read, the brigands often chose their victims with care. They did not just wait for whoever came along. In one of the stories, an accomplice in the town informed the outlaws who was setting out on a journey. Was it Chaereas and Callirhoe or Leucippe and Clitophon? In his memory they had all merged into one over the years. The column had hardly left Zeugma before the bandits struck. That could well be chance. But something Quintus had said afterwards had stuck in Valens’s mind. It was their behaviour. They had not gone for the rich pickings of the mule train, but attacked the armed men and killed Severus. In retrospect, the killing of the commanding officer seemed almost as if it were deliberate.

And later, in Adiabene, there was the matter of the water bottle dropped in the flight to the River Lykos. It had given Valens the idea to lead the tent-dwellers into the ambush. At the time he had been angry, put the discarded item down to carelessness. But had someone before himself been leaving a trail for their pursuers?

Yet why would anyone in the expedition seek to betray them? Of course all, except himself, were frumentarii. They lived in a world of treachery. If there was a traitor, who could it be? Zabda would have been his main suspect. The Palmyrene was a thief, mistrusted by the others, especially by Hairan. Before they had set out, Zabda had drawn a knife on Valens in that bar. But Zabda had given his life to save him.

Nothing had gone wrong since the canyon. Perhaps the traitor was biding his time.

The singer ended, the audience applauded quietly, and the serving girls brought in the sweetmeats.

Perhaps there was no malign hand at the heart of the column. Bad things just happened. Most likely it was all a figment of his own imagination.

As the gourmet on his right was addressing himself to the pastries with a zeal that precluded conversation, Valens turned to make himself agreeable to Lucia. She encouraged him to take a delicacy flavoured with apple juice, honey and cardamom.

‘You must be relieved to be back at home,’ he said.

She smiled, although without much conviction.

‘And your late husband’s brother will take you as his wife.’

‘Yes.’ The smile faded.

‘It is not our custom in Rome, but each people have their own.’

She did not reply, but it did not take a physiognomist, or some other expert in the human psyche, to see she was less than delighted.