‘Not what the boys think.’ Aulus looked around for support. Narses and Zabda held his eye. The others looked at the ground.

‘This is a Roman army unit, not some Greek democracy,’ Valens snapped. ‘We go where I say.’

‘Two men dead, and we are not in enemy territory yet. We must go back while we still can.’

‘No.’

‘Without Quintus we have no way of plotting our course.’ There was an ugly, stubborn and belligerent cast to Aulus’s aged and pouched face. ‘We could wander these wastes until we die of hunger and thirst, or until the tent-dwellers pick us off one by one.’

‘Nonsense.’ Valens affected a certainty that he did not feel. ‘We have supplies for several days, enough water, the Arabs are nothing to fear, and Quintus taught me to navigate by the stars. We follow the sinking of Arctophylax and Cynosura to the east. Soon we will reach the Tigris. Once we are in the realm of the King of Kings, Narses is a Persian and can guide us.’

Narses cleared his throat. ‘I once served in Hyrkania, did a tour of duty at the Castle of Silence – the Lord Mazda be praised for bringing me safe from that lonely place – but I do not know the mountains that we must cross in the province of Matiane to reach the Caspian.’

‘Then once across the Tigris, we hire a native guide.’ Valens was adamant. ‘You and Hairan speak Persian. And money is a universal language.’

Zabda spoke, although somewhat reluctantly. ‘I have the Persian tongue as well. The wealth of Palmyra depends on their trade.’

‘All mercantile endeavour is trickery and fraud,’ Iudex said. ‘If I pray, the Demiurge will set my spirit-guide on the right path.’

‘Your spirit-guide?’ Aulus spat, sacrilegiously near to the corpse. ‘A human guide might be more reliable.’

‘Enough.’ Valens drew himself up, tried to radiate authority. ‘We will search for the strayed animals, see to those we find and those that remain. Then we will return and bury Quintus. Those are your orders. Carry them out.’

Valens saw Aulus look at Iudex.

‘We will do what is ordered, and at every command we will be ready,’ Iudex said.

One by one the others repeated the words. Aulus last, and with utmost reluctance.

We will do what is ordered, and at every command we will be ready.

No one had spoken the ritual with any enthusiasm, but they began to walk back to the dry watercourse.

‘Did Quintus really teach you?’ Hairan spoke quietly to Valens.

‘It is not difficult. Anyway, ride into the rising sun, and we will reach the Tigris.’