Eventually they reached the rockface. The young optio Gaius Licinius Prosper gestured for them to start climbing. If I die to satisfy your ambitions, I will come back and haunt you, thought Castricius as he slung his shield on his back and began to ascend. Since the young optio had foiled the plot to burn the granaries he had made little secret of his ambition. Down by the river the far cliff face of the southern ravine was quite steep. It was this that had attracted the attention of Prosper: 'The Sassanids will never expect a night raid from that quarter.' Well, we will soon find out if you are right, young man.
Castricius was one of the first to the top. Heights held no fears for him and he was good at climbing. He peered over the lip of the ravine. About fifty paces away was the first of the Persian campfires. Around it he could see the huddled shapes of men wrapped in cloaks sleeping. There was no sign of any sentries. From some distance came the sounds of talking, laughter, snatches of song. Nearby, there was no sign of anyone awake.
When the majority had caught up, Prosper just said, 'Now'. There were an undignified few moments as everyone scrambled over the edge of the ravine, rose to their feet, slid their shields off their backs, drew their swords. Miraculously, the Sassanids slept on.
With no further word of command, the ragged line of volunteers set off across the fifty moon-washed paces to the campfire. Maybe, just maybe, this is going to work, thought Castricius. Along with the others, he accelerated into a run. He chose his man: a red cloak, hat pulled down over face, still not stirring. He swung his spatha.
As the blade bit, Castricius knew that it was all about to go horribly wrong: they were in a trap, and he was very likely to die. The blade sliced through the man-shaped bundle of straw. Automatically, Castricius sank into a very low crouch, shield well up – and not a moment too soon, as the first volley of arrows tore through the Roman ranks. Arrowheads thumped into wooden shields, clanged off chainmail coats and metal helmets, punched into flesh. Men screamed.
A blow to his left temple sent Castricius sprawling. It took him a moment or two as he retrieved his sword and got back to his feet to realize that it was an arrow, that they were caught in a crossfire.
'Testudo, form testudo,' shouted Prosper. Bent very low, Castricius shuffled towards the optio. An arrow whipped past his nose. Near him a man was sobbing and calling in Latin for his mother.
A trumpet sounded, clear and confident in the confusion of the night. The arrows stopped. The Romans looked around. There were about twenty of them left, in a loose knot rather than a parade-ground testudo.
The trumpet sounded again. It was followed by a rising chant: 'Per-oz, Per-oz, Victory, Victory.' Out of the darkness swept a wave of Sassanid warriors. The firelight glittered on the easterners' armour, on the long, long blades of their swords, and in the murderous look in their eyes.
'Fuck me, there are hundreds of them,' said a voice.
Like a wave crashing on a shore, the Persians were on them. Castricius parried the first blow with his shield. He swung his spatha low, palm up in from his right. It swung under his opponent's guard, biting into the man's ankle. The impact jarred back up Castricius's arm. The Sassanid fell. Another took his place.
The new enemy swung overhead. As Castricius took the blow on his shield, he felt and heard it splinter. From his left a Roman sword darted forward and tried to take the Persian in the armpit. Sparks flew and the point of the blade glanced off the easterner's mail. Before Prosper could pull back from the blow, another Sassanid blade flashed in and severed his right hand. Castricius watched horrified as the young optio spun round and sank to his knees, his left hand holding the stump of his right arm, his mouth open in a soundless scream. There was blood everywhere. The two Sassanids moved to finish the officer. Castricius turned and ran.
Boots stamping on the rock, Castricius flew back towards the edge of the cliff. He threw away his shield, dropped his sword. As he neared the lip of the ravine he threw himself sideways and down, sliding the last few yards, swinging his legs out first into space, twisting his body, his fingers scrabbling for purchase. For a moment he thought he had misjudged it, that he would slip backwards clear over the edge. The cliff had a hundred-foot drop here. If he fell he was dead. Sharp strong pain as his fingernails tore, but he had a grip. Sliding, scrabbling, boots missing toeholds, legs often dangling, he shinned down the face of the ravine.
High on the south-west tower of Arete, although he was at least 400 paces away, Ballista saw the trap close quicker than some of those caught in its jaws; the twang of bowstrings, the screams of men, the two clear trumpet blasts.
'Bugger,' he said succinctly.
'We must help them,' Demetrius blurted.
Ballista did not reply.
'We must do something,' the Greek boy continued.
'Sure it would be good,' said Maximus, 'but there is nothing to be done. It will all be over by the time we get any troops there. And, anyway, we cannot afford to lose any more men.'
Ballista watched for a while in silence, then said that they should go to the southern wicket gate, in case there were any survivors. Climbing down the steps from the Porta Aquaria, the northerner turned things over in his mind.
Ballista had been driven by the words dinned into him by his mentors in fieldcraft: a passive defence is no defence at all. An inactive defence not only hands all the initiative, all the momentum to the besiegers, it undermines the defenders' discipline, their very will to resist. So, since the burning of the ram, Ballista had quite frequently sent out small nocturnal raiding parties. But his heart had somehow not been in it.
The death of Antigonus had changed things. In Antigonus he had lost a master of clandestine operations. How the northerner missed him. Ballista thought back to the masterly way in which Antigonus had wiped out the Sassanids left stranded on the island in the Euphrates after the first failed assault on the city: twenty dead Persians, and not one Roman had fallen. Among the high reeds that night, death had come to the terrified easterners with bewildering speed and efficiency. The raiders Ballista had sent out since had tried their best, but the results had been mixed. Sometimes they were spotted and the mission abandoned near the start. As often as not they took as many casualties as they inflicted. And now, tonight, there was this unqualified disaster. Whatever the textbooks said, whatever the doctrines of his mentors, Ballista would send out no more raids.
Ballista stood by the open wicket gate and thought of Antigonus. It was strange how in a very brief time he had come to rely on him. It was one of the strange things about warfare – it quickly formed strong bonds between unlikely men, then with death it could even more suddenly break them. Ballista remembered the artillery ball taking off Antigonus's head; the decapitated corpse standing for a few moments, the fountain of blood.
Lungs burning, limbs aching, sweat running into his eyes, Castricius plunged on through the reed bed. He had hurled away his helmet, ripped off his mail coat when he reached the foot of the cliff. In flight lay his only hope of safety. On and on he ran, the date palms waving above his head, stumbling as roots twined round his legs. Once he fell full length in the mud, the breath knocked out of him. Fighting the exhaustion and despair that told him just to stay where he was, he struggled to his feet and plunged on.
With no warning, Castricius was clear of the reed beds. Ahead in the moonlight was the bare rock floor of the ravine; on the far side of it a group of torches along the low wall and around the wicket gate. There was no sound of pursuit. He set off at a run nevertheless. It would be a shame to get this far, so close to safety, and then be cut down.