‘When we surrendered, the general Ballista gave us his word that we would never have to fight our own people.’

‘You have sworn the sacramentum to the Roman Emperor,’ Valens said, ‘and at Zadrakarta you took an oath by Mazda never to desert or betray our brotherhood.’

‘I need no reminding. We are raised to ride, shoot the bow, and abhor the Lie.’

‘What will you do?’ Valens asked.

Narses blew out his cheeks, exhaling noisily. ‘I will not betray or desert the brotherhood. But, if I can avoid it, I will not take a Persian life.’

‘A man cannot go into a fight with one hand tied behind his back,’ Valens said. ‘You will get yourself killed.’

Narses did not reply.

‘You might get one of us killed.’

Narses sighed, but still did not speak.

‘An oath taken under duress is not binding,’ Valens said. ‘Perhaps an action born out of necessity is not blameworthy.’

Narses would have snorted with derision had it not been impolite. ‘You sound like one of those hairy Greeks, a sophist or a philosopher.’

Valens grinned. ‘Gods below, I loathed my philosophy tutor. All that logic-chopping and convoluted semantics do nothing to prepare a man for life.’ He stopped smiling, suddenly very serious. ‘You must do what you think is right, but we have to trust one another.’

‘We have to trust one another,’ Narses repeated.

*

The convoy plodded slowly up the track between the cliff and the precipice. They had been on the road for days, but in a couple of hours they would reach the Castle of Silence. The eight draught horses were labouring against the incline to pull the heavily loaded wagon. The squeal and rumble of its wheels drowned the sound of the hooves. The men were as tired as the animals, too tired to talk. There was nothing to see but the endless ravines and bare slopes and the little gullies choked with juniper and mountain scrub. It was cold and threatened to rain.

A hot meal and a warm fire were the only good things to anticipate about their arrival. The fortress was a dismal place, its warden feared almost as much by the soldiers as the prisoners. The few whores provided for the troops were pale, sad and listless things. At least the convoy would not remain longer than a few days, just long enough to restore the horses. They were better off than the poor devils of the garrison. Two months cramped in that remote eyrie was a harsh penance, even in summer, and winter was fast approaching.

They crested a rise and saw something on the road at the foot of a gully.

The outriders stiffened in their saddles.

It was a man. He was on his back, unmoving.