The clibanarii were still walking, but now they gripped their lances two-handed, and brought them down. A wicked wall of sharp steel glittered for a moment, until the shadows swept over the Sassanid horsemen.

A trumpet called, and the Persian nobility urged their warhorses to a trot.

No more than thirty paces separated the fighters. Yet Naulobates kept to a sedate pace.

The Sassanid trumpet sounded again, and the armoured knights moved to a canter.

The ground shook with the thunder of their coming. The air itself seemed to tremble.

Naulobates and his men nudged their ponies to keep just out of reach.

Now the storm front hit. Curtains of rain streamed down from the north, flattening the grass, stinging Valens’s face.

Through the murk, he saw that the pursuit on the two flanks was drawing away fast. The riders of neither Artemidorus or Andonnoballus were making for the camp. Instead both were angling away across the limitless Steppe. Soon they would be lost from sight.

Squinting ahead through the driving rain, Valens was amazed to see how far they had come. The trees along the river were no more than a mile away. The day would be decided soon.

Maddened by their quarry always remaining just out of reach, and goaded by the gadfly arrows of their elusive foe, the Persian nobility could take no more. With or without orders they charged at the gallop.

Now the Heruli rode hard. The small shaggy ponies surged past Valens and his men. The thousands of horrible spear tips were almost at Valens’s back. He bent low over the neck of his horse, driving it forward with all his strength. Drawing his bow, he used it as a whip.

As they pounded across the plain, the Sassanid ranks broke. The better mounted pulled ahead. They bellowed the names of their clans, riding for the honour of first striking down these cowardly barbarians. Gaps opened in their frontage. But still they came.

Suddenly Naulobates and the riders in front of Valens vanished, as if swallowed by the earth.

Terrified as he was of the Persian spears so close to his shoulder blades, Valens reined back. They were at the river. Thank all the gods, Naulobates had ridden down one of the draws. Leaning back in the saddle, Valens followed him down, his mount almost on its hocks.

The Rosomoni to either side had to jump from the high bank. Valens saw one pony fall. But these nomads had been in the saddle before they could walk. Riding was more natural to them than walking. They and their ponies could negotiate almost anything.

The track up from the riverbed was muddy from the rain, trampled by the hooves of those who had gone before. Valens’s mount slipped and staggered up the far side.

Emerging at the top of the bank, he swung away to the right. His men were still with him.