The two troopers sheepishly went inside. Cocceius started to move.
'No.' Demetrius almost shouted. 'The Dux heard the sounds of tunnelling. He has gone to spy out where the Persian mine is being dug.'
Acilius Glabrio rounded on him. 'And what have we here? The barbarian's little bum boy.' He stepped close to Demetrius. He smelt of carnations. The torchlight highlighted the little ruffs of beard that were teased out in curls from his neck. 'What are you doing here? Selling your arse to this decurion and a few of his troopers so that they open the gate and let you desert?'
'Listen to the boy, Dominus. He is telling the truth,' Cocceius said.
The intervention attracted the full attention of Acilius Glabrio. Now the young patrician's anger was palpably genuine. Turning from Demetrius, he approached the decurion. 'Have I not warned you? Inside now.'
Cocceius dared a final appeal. 'But Dominus, the Dux… we cannot just abandon him out there.'
Forgetting the sword at his side, Demetrius bent down and picked up a rock.
'Are you disobeying a direct order, Decurion?'
Demetrius felt the rock sharp and gritty in his hand. The curls on the back of Acilius Glabrio's head shone in the torchlight.
'Ave, Tribunus Laticlavius.' A voice came from beyond the torchlight.
Acilius Glabrio whirled round. His sword rasped from its sheath. He crouched, his body tense.
Two ghostly figures, blackened and streaked with dust, emerged into the circle of light. The taller pulled a cloth from his head. His long fair hair fell to his shoulders.
'I must congratulate you, Tribunus, on your diligence. Patrolling the ramparts in the dead of night, most admirable,' Ballista said. 'But now I think that we should all go inside. We have much to discuss. We have a new danger to face.'
XV
Ballista went to take a last look at the Persian siege ramp. He peered out from behind the makeshift parapet. Virtually every day the Sassanid artillery smashed the parapet to pieces. Then that night the defenders rebuilt it.
Despite the thick cloud of dust the progress of the ramp was clear enough. The Persians had begun work thirteen days before the kalends of August. It was now nine days before the kalends of September. Counting inclusively, that was thirty-six days' work. In thirty-six days the ramp had inched forward some forty paces and been slowly lifted up almost to the level of the parapet of the town wall. The ditch in front of the wall, which had taken the defenders such trouble to dig, had been packed with rubble. A gap like a canyon still separated the ramp from the defences. But the canyon was only about twenty paces wide, and it was partly filled by the defenders' own earth bank up against the wall. When the canyon was filled the Sassanid storming party would have a final approach over a level land bridge some twenty-five paces wide.
The progress of the siege ramp had been bought at the cost of the back-breaking labour of thousands. Every morning in the grey light of pre-dawn the Persian vinae, the mobile shelters, were pushed forward and joined together to form three long covered walkways. Under these, lines of men laboured to bring up the earth, rubble and timber that those at the front, protected by stout screens, dropped down into the space before the ramp. At the sides of the ramp more workers, again protected by screens, levered and mortared into place the mud bricks which formed the retaining walls.
The ramp's progress had been bought at the cost of the lives of many, many men in the Sassanid ranks. Soon after work had begun Ballista had sited the town's four twenty-pounder artillery pieces behind the wall in line with the ramp. Several houses had been demolished to create the new artillery emplacement. Those property owners that could be found had been promised compensation – should the town not fall. Every morning the vinae had to advance on the same lines, and then stay in place throughout the long day. Every morning the ballistarii in charge of the twenty-pounders, having checked the settings of their weapons, could fire blind at a high trajectory over the wall, reasonably confident that, sooner or later, with help from the spotters on the wall, one of their smooth round stones would hit one of the vinae at terrifying speed; would smash its wood and leather and reduce to a sickening pulp the men labouring in the illusory safety beneath.
As soon as the look-outs on the wall shouted, 'hit, hit,' the defending bowmen would emerge from the shelters they had dug in the base of the town's internal glacis, sprint up to the battlements and pour a devastating hail of iron- and bronze -tipped arrows into those Sassanids exposed as they feverishly worked to repair or reposition the vinae.
Ballista had ordered that the two six-pounder artillery pieces sited on the towers at the threatened stretch of wall concentrate on the bricklayers working on the ramps' retaining walls. The ballistarii in charge of these had a clear line of vision. The screens could not withstand repeated impacts. Here again, over time, the slaughter was immense.
The Sassanid artillery had done what it could to destroy its counterparts. But so far they had been unable seriously to curtail the havoc caused by the defenders. Ballista had had to replace both the six-pounders and most of their crews twice, and one of the twenty-pounders had been smashed beyond repair. There were no further reserves of stone-throwers. Yet the volume of shooting had been little reduced.
As Ballista watched, a six-pound stone moving almost too fast to see crashed into one of the screens shielding the bricklayers. Splinters flew, a cloud of dense dust erupted, the screen seemed to buckle, yet it remained in place. Another one or two of those and that will be another gone: more dead reptiles, and another delay.
Ballista ducked back behind the parapet. He sat down, resting his back against it, thinking. Every night the Sassanids withdrew to start again the next morning. Why? Why did they not work through the night? They had the manpower. If Ballista had been their commander they would have done. The northerner had read somewhere that under the previous eastern empire, that of the Parthians, there had been a reluctance to fight at night. Maybe it was the same with their Persian successors. Yet they had been digging the mine from the ravine at night. Possibly it took something special to drive them to it. It was a mystery – but war was one long series of inexplicable events.
'I have seen all I need for now. Let us go down.' Crouching, Ballista moved to the stairwell in the roof of the tower, and down the stairs. He walked the few paces to the northern of his two mines. Castricius was waiting just inside. Ballista waved his entourage in first: Maximus, Demetrius, the North African scribe, two messengers and a couple of equites singulares.
'We can talk here.' Ballista sat down. Castricius squatted down next to him, Demetrius near by. Ballista noted the solid-looking lintel, the thick pit props. It was not too bad here, just near the entrance. The oppression of the enclosed space could not overwhelm him when it was but three or four steps from the open air.
On the other side of the mine a line of men passed baskets of spoil from hand to hand out of the tunnel.
Castricius produced several scraps of papyrus, all covered in his scrawled writing. He expounded with admirable clarity and brevity the course of his tunnel. It was under the wall, under the outer glacis, and was scrabbling like a mole towards the Persian siege ramp. Consulting one piece of papyrus after another, he outlined his projected needs for pit props and slats to hold up the sides and roof, lamps and torches to light the work, and various incendiaries and their containers for the ultimate purpose of the mine. As Ballista approved the figures, Demetrius wrote them down.
Castricius went to check on progress; Ballista sat in silence where he was. A Sassanid missile thundered into the wall above. A fine shower of earth fell from the roof. Ballista, from wondering if the opposite pit prop was slightly off centre, found himself thinking about Castricius and his changes of fortune. He must have committed a terrible crime to have been sent to the mines. He had survived that hell, which spoke of uncommon resilience; he had joined the army (was there a regulation that should have prevented that?); finding the corpse of Scribonius Mucianus had brought his knowledge of mines to the attention of his Dux; being one of the three survivors of the ill-fated expedition of the young optio Prosper had won him the post of standard-bearer to Ballista. Now, for a second time, his experience of the mines had aided him, bringing promotion to acting centurion to dig this tunnel.
Another stone hit the wall; more dust drifted down. From this mine and the mutability of fortune, Ballista's
