Ballista quietly, and he hoped calmly, explained what he was about. The aim could not be simpler: they were to break through the group of Sassanids closest to the river. With luck, the Persians would be taken by surprise as they charged out of the shelter of the date palms. Again with luck, this group of Persians down by the river would at that moment be out of sight of the others up on the plateau, buying the Romans just a little time. Anyway, once through the nearest group, the Romans would ride flat out for Arete and safety. With yet more luck, the night would hide them from the pursuing enemy.
It was growing dark among the date palms. The shadow of the cliff stretched out across the Euphrates. The temperature was dropping quickly. The wind worried at the palm fronds and tamarisks. The waters sucked at the banks. It was hard to hear anything clearly and difficult to see in the gathering gloom. Somewhere on the other side of the river a jackal barked.
'How do you know we are in a trap?' Maximus whispered, his mouth very close to Ballista's ear. The northerner took his time replying, wondering how to put his suspicions into words.
'The Sassanids between us and Arete are not acting like a normal scouting party looking for information. If that is what they were they would have chased the one of us they saw, chased him flat out – catch him and they could go home, out of danger. Instead they are moving south at a slow walk, strung out across the plain between the river and the hills. They have been sent on a flank march to catch any of us who escape from the main ambush. That line of dust in the sky to the south – it might just be the wind, but to me it looks all too like the sort of dust raised by a lot of cavalry moving fast.'
The sound of a scatter of stones and the first of the Persian horsemen appeared. They rode out of the wadi and on to the floodplain, advancing in the gathering gloom. As the scout had said, they were light cavalry, horse archers. Dressed in tunic and trousers, they were unarmoured. One or two had metal helmets, but the majority were bareheaded or wore just a cloth cap or bandana. Each had a long cavalry sword on his left hip, some had a small round shield on their left arm. There seemed to be at least fifteen of them. If they had ridden in any particular order, it had been dissipated by the descent into the ravine. Now they rode in a loose group, three horses across and four or five deep. They came on at a walk, their horses stepping delicately.
The Sassanids were getting close. Even in the gloom Ballista could make out their long hair, the glitter of their dark eyes. They were getting too close. Any moment now one of them would see the immobile forms waiting in the deeper shadow of the palm grove. Ballista could feel his heart beating as he sucked in air to fill his lungs.
'Now! Charge! Charge!' he yelled, kicking his heels into Pale Horse's flanks. There was a second's pause as the gelding gathered his quarters and then they were crashing through the reeds which fringed the grove and hurtling towards the Persians. There were exclamations of surprise, shouts of warning. The enemy tugged swords from scabbards. Their horses had come to a halt, some wheeling pointlessly. Ballista aimed at a point between two of the leading Sassanids. As he shot between them the northerner directed a vicious cut at the head of the Persian on his right. The man blocked the blow. The shock jarred Ballista's arm.
There was virtually no gap between the next two Sassanids in front of the northerner. He jabbed his heels into Pale Horse and set him at them. The gelding's left shoulder crashed into the withers of the Persian horse to the left. It staggered back. A gap opened, but the impact had robbed Pale Horse of all momentum. Ballista kicked furiously. His mount responded, leaping forward. To his right he saw Maximus's blade topple first one then another Persian out of the saddle.
They were nearly through; just one line of Persians still ahead. Maximus was no longer right on his shoulder. Ballista drew his spatha back over his left shoulder and aimed a mighty downward cut at the Sassanid to his right. Somehow the man blocked it with his shield. Ballista wrenched his blade free of the splintered wood and cut horizontally over Pale Horse's ears at the man on his left. This time he felt the blade bite home. There were no more enemy in front.
The force of the blow smashed Ballista's head forward. His nose crunched into Pale Horse's neck and blood poured from it. It was broken. He could feel more blood running down the back of his neck. Instinctively he twisted round to the right, bringing his spatha up in an attempt to parry the next blow he knew would come, the blow meant to finish him.
There was the Sassanid, sword arm raised. The bastard smiled – and looked down, clutching his side, staring stupidly at the sword wound.
Ballista waved his thanks to the Spaniard and kicked on. The scribe grinned back and flourished his sword – then the look on his face changed to shock. His horse disappeared from beneath him. He seemed to hang for a moment, then he went down into the tumbling, sliding mass of his own horse and under the hooves of the following Roman and Sassanid mounts alike.
There would be time for pity or guilt later. Ballista could not have stopped Pale Horse in any case. They rushed on, up the wadi, up its steep bank. As they emerged on to the plateau it grew much lighter. Up here the sun had not quite set. Without looking to see who was still with him, Ballista set the pace at a hell-for-leather gallop. He angled away from the road towards the north-west. It was vital that they pass inland of the next ravine.
The northerner looked over his left shoulder. There was the next group of Persians, about twenty of them. They had turned and were now riding hard to cut Ballista and his men off. Their long shadows flickered over the plain. The other groups of Persians had also turned, but they could not possibly reach the ravine in time; for now they were of no concern.
Ballista heard Maximus shout something. He ignored him; he needed to think. Despite the growing ache in his head, his mind was clear. He was calculating the distances and the angles. He saw it all as if watching from a great height: the fixed point of the head of the ravine, the two moving bodies of horsemen converging on it. He leant forward in the saddle, pushing Pale Horse for just that last bit of effort, that last pace or two of extra speed.
Ballista and his men made it with a little bit to spare. They skidded round the mouth of the ravine with the Persians still fifty paces away. They pushed on, but some of the urgency seemed to have gone out of the pursuit. Soon they were a couple of hundred paces ahead. Ballista slackened the pace. It was now twilight. There was something that had to be done. He did not want to do it, but it could not be deferred. He looked round to see who had fallen.
Maximus was there. Demetrius was there. Romulus was there, and four equites singulares, one scribe, both messengers and three servants, the latter commendably still leading their packhorses. The butcher's bill could have been higher – three soldiers, one Spanish scribe and two servants. It could yet mount higher, much higher.
The moon was up, but the strong south wind was pushing tattered clouds across its face.
'Are you all right? You look terrible,' Maximus called.
'Never better.' Ballista replied sourly. 'Like a slave at Saturnalia.'
'Do you think they will give up?' Demetrius asked, trying but failing to keep the desperate wishful thinking out of his voice.
'No.' It was Maximus who firmly crushed his hopes. 'They are settling in for the long haul. They intend to run us down during the night.'
As the Hibernian spoke, a series of twinkling lights appeared strung out between the river and the hills.
'Do we still have a lantern?' Having been assured by one of the servants that they still had two, Ballista ordered one of them to be lit. The order was obeyed amid unvoiced horror. Bright golden light spilled out around them.