‘Dulce et decorum est . . . I am not so sure it is sweet and fitting to die for your country.’ A strong but unreadable emotion burned behind Clemens’s eyes. ‘You are right, we will do what is ordered, and at every command we will be ready.’

They rode on in an awkward silence. Clemens returned to studying the surrounding hills. One persistent fly buzzed incessantly into Valens’s face.

‘Look!’

Clemens reined in, and pointed.

Valens’s eyes followed the outstretched arm, ahead and to the left.

A shadow moving down an incline. No, there were no clouds. Not a shadow. Men on horses, moving fast. There must be twenty or more. They were aiming for the head of the column. A fold in the ground prevented Severus and the others seeing their approach.

‘With me!’ Clemens booted his horse forward.

Caught unaware, Valens gathered his reins and pressed his mount to follow.

They overtook Decimus and the baggage train.

Hardly slackening his pace, Clemens shouted, ‘Raiders! Circle the mules, tether the led horses inside. You three, stay and guard them.’

Narses and Zabda sat looking around for the threat. Decimus bellowed at them, and, long accustomed to obey, they sprang into activity.

‘Valens, you follow me,’ Clemens said.

The horsemen burst over the crest, not thirty paces from their target.

Although taken by surprise, Severus and his three companions did not hesitate, but turned their mounts and reached for their weapons. Without time to draw their bows, they went for their swords.

As the attackers thundered down, they hurled a volley of javelins. A Roman horse went down. Valens saw its rider jump clear. In an instant the two sides met, and the space was transformed into the wheeling confusion of a cavalry skirmish.

Clemens was about four lengths in front. Valens saw the veteran readying his sword and shield. Fool that he was, Valens had not thought to do that himself. He dropped the reins on the neck of his horse, and fumbled to free the laces that tied his shield to a horn of his saddle. The motion of the galloping horse, and his nerves, made his fingers clumsy. At last the knot came undone. Gods below, he nearly dropped the thing. Now they were almost upon the fight. Desperately, he yanked out his sword.

The enemy were circling around the outnumbered Romans. They stabbed down at the figure on foot. It was Severus. The officer twisted this way and that, defending himself.

The attackers saw the two riders coming and drew back. Clemens charged into the gap. Valens urged his mount behind. They clattered to a halt on either side of Severus.

For a moment they were the calm in the eye of the storm. The sounds of the others fighting came as if from a great distance.

‘Good of you to join us,’ Severus said.