‘It is insane,’ Hairan said, ‘but brilliant. I have always loved you – although not in the way your mother did.’

‘We have to leave.’ Iudex took a last look into the water, then tipped it away. ‘Now. We are in danger.’

The laughter had died.

‘Anything?’ Valens called up to Aulus.

‘Nothing.’

Valens hesitated. Better to look foolish than to die. ‘Mount up, quickly, no noise.’

They rode down the river, keeping their horses in the stream, hoping the waters might obliterate their tracks. Two smaller watercourses ran off from the river to the west, and after a quarter of an hour a larger one opened into it from the east. They turned into the latter. After no great distance, a grove of willows stood on its banks. They hobbled the horses and left them drinking. Climbing out under the trees, they established a perimeter defence, with the majority of men facing back the way they had come.

They had not long to wait.

A trumpet rang across the plain. At its command, Persian warriors erupted from both banks of the river just south of where they had been camped. Yelling high, thin war cries, the Sassanid horse archers raced to encircle the campsite. Drawing near, they loosed volleys of arrows to drop near vertical down into the riverbed.

‘They will be most disappointed,’ Hairan said.

‘What do we do now?’ Clemens said. ‘We can see them, and when we move they will spot us.’

Valens turned to Narses. ‘How far to the sea?’

‘A long day in the saddle.’

Chapter 31

CHAPTER 31

The Walls of Alexander

THE NEW MOON HUNG LOW over the Caspian. The storm of the day had blown itself out, but the wind was still cold from the north.

From his post on watch, the westernmost fortress stood stark against the night sky. The great wall itself stretched eastwards across the featureless plain until it was lost in the gloom. No one knew when the Walls of Alexander had first been erected. The name of the Macedonian was often given to any structures that were impressive, and whose origins were lost in time. Whoever first designed them, their intention was to keep out the nomad tribes of the Steppe, but they also formed a formidable barrier to anyone attempting to leave the realm of the King of Kings.