'I shouldn't be surprised,' Cato replied bleakly. 'Another twist of the knife. What have your lads been saying, then?'

'Nothing to my face. It's more the tone of their comments and the generally sour ambience whenever I'm around. Of course, I don't give a flying fuck about how they feel towards me. Just as long as they do as they're told.All the same, we'd better keep an eye out for any further trouble between the legionaries and the auxiliaries. Last thing we need is for them to be watching their backs when they should be looking out for the enemy.'

'Quite.' Cato took a last glance round the camp before he eased himself down on to the ground and tried to make himself comfortable under his cloak. But despite the heat of the day the nights were cold and he could not help shivering. He knew that it would be a while before he managed to get to sleep, if he ever did.

'Macro?'

'Hmm?' Macro grumbled drowsily. 'What? What is it?'

'What are your plans when we reach Palmyra?'

'Plans?' Macro paused before replying. 'Longinus did not have much to say on that front. Just that we are to cut through to the citadel and hold it until he arrives.'

'That's assuming that Artaxes and his followers haven't taken the citadel yet.'

'Yes.'

'And if they have?'

'Then we've pretty much had it. Our water will be finished by then so there'll be no possibility of retreat. We'll have to take Palmyra by ourselves, or surrender.' Macro chuckled. 'It's the same old story. Death or disgrace. Some choice, eh?'

'Some choice,' Cato agreed quietly.

'Still, nothing to be done about it,' Macro concluded.'So do me a favour and shut up and get some sleep.We need all we can get.'

Macro turned his back to Cato and pulled his cloak tightly round his stocky body. A short time later he was asleep and his rumbling snores added to the more distant chorus of the other men, broken here and there by the low voices of the restless and the occasional snort and whinny from the horse lines. But there was no sleep for Cato as his mind dwelt on the situation. The odds were stacking up against them and while he understood the need for the governor to send a relief force to Palmyra it appeared to Cato that their mission was little more than a desperate gesture. King Vabathus might already be dead, along with the ambassador and his small retinue. Even now Artaxes could be cementing his grip on the throne, and throwing his kingdom open to Parthia. If that happened then the delicate balance of power that had kept the peace in the east of the Empire would be shattered. Parthia would be able to mass its fast-moving army on the very frontier of Syria and threaten Roman territory from Armenia to Egypt. Emperor Claudius would be forced to reinforce his eastern armies at huge expense, and strip legions from the Rhine frontier, already thinly stretched. That, or abandon huge swathes of land to Parthia and risk the ire of the mob and political rivals in Rome.

It could all have been avoided, Cato realised. If only Rome had been content to leave Palmyra as a buffer between the empire and Parthia then peace could have lasted, albeit an uneasy peace. But the moment the treaty had been signed with King Vabathus, a confrontation with Parthia was assured. Cato felt a cold rage grow within him as he contemplated the policymakers back in Rome, living lives of luxury far from the consequences of their power play. Perhaps they had calculated that their designs on Palmyra justified the risk of provoking the Parthians, as one might wager a stake on the roll of a dice. But here on the frontier that stake was measured in the lives of the men sleeping in the darkness all around Cato. Men whose endurance would be stretched to the limit in the days ahead, before they even had the chance to close with the enemy. If they won, then a token would be shifted fractionally on the map of the Empire back in Claudius' palace in Rome. If they lost, then the token would be casually swept from the board and discarded.

Cato smiled bitterly at the thought, and cursed himself for possessing this cruel streak of detachment that caused him to view his actions in the widest context. For a while he glanced at Macro's slumbering form with envy. Finally, a long time after almost all the other soldiers had fallen still and silent, Cato eventually drifted off into a troubled sleep on the cold, hard ground.

The next day the column left the hills and emerged on to the rolling dusty plain on the road to Chalcis. Despite Macro's concerns, they encountered only the usual trade caravans from which the men hurriedly bought fruit and wine at vastly inflated prices. All the while the number of stragglers increased and by the time they reached Chalcis, three days after leaving Antioch, Cato saw from his strength returns that eight men of the Second Illyrian had failed to reach the camp in time for that morning's roll-call. He sat in the shade of the palm trees that fringed the small lake on whose bank the town of Chalcis squatted. Like the other towns that had been founded on the ancient trade routes, Chalcis profited from levying taxes on the caravans of camels that passed through its territory, and its inhabitants lived with an enviable degree of comfort. But now, news of the revolt in Palmyra and rumours of the inevitable conflict between Rome and Parthia had unsettled the people and small crowds gathered to watch the Roman column as it marched up to the town and halted to rest and fill its canteens and spare waterskins at the lake.

Cato could well understand their anxiety. The isolation that made peace so profitable for Chalcis also made it vulnerable in time of war, and its strategic importance meant that it would be contested by both sides.The income from trade would dry up and the town faced hard times, if it survived at all. Cato focused his mind on the strength returns on the waxed slate that Centurion Parmenion had brought to him.

'Eight men now. I wonder how many more we will have lost by the time we reach Palmyra?'

'Shall I send a cavalry squadron back to round them up, sir?'

Cato considered this for a moment and shook his head. 'If they're able to, they'll find us. But I'll not lose any more men than I have to by sending out search parties. Mark them down as absent without leave. If they fail to catch up by tomorrow morning then put them down as deserters.'

'Very well, sir.' Parmenion scored a note on his tablet and Cato watched him for a moment before speaking in a low voice.

'What's the mood of our men?'

Parmenion looked up at his commander, then glanced round to make sure that they would not be overheard. 'Not too bad, considering.'

'Considering what?'

Parmenion nodded towards the legionaries sitting beneath the palms a short distance from the men and horses of the Second Illyrian.'There's still plenty of bad blood over that business in Antioch. The legionaries are needling our lads at every opportunity. Frankly, they're spoiling for a fight.'

'Who, our men, or Macro's?'

'Both.' Parmenion wearily rubbed the bristles on his chin.'Wouldn't take much to set them at each other's throats.'

'We must see that it doesn't happen,' Cato said firmly. 'I want you to pass the word on to the other centurions and their optios.We can't afford any trouble. I'll come down like a bloody avalanche on any man who causes a fight. Make sure that's understood.'

'Yes, sir.'

'Very well then, Parmenion. Carry on.'

His adjutant closed his wax tablets, saluted and then strode off towards the handful of mule carts that carried the cohort's records, pay chest and small stock of spare weapons and rations. A party of auxiliaries was busy loading the filled waterskins and baskets of fruit and dried meat bought from the market in Chalcis. Cato regarded them for a moment, and wondered briefly if he had allowed for adequate supplies to see his men across the desert to Palmyra. It had been a difficult calculation. Of all the supplies that a commander had to provide for his men, water was the most onerous, thanks to its weight, and propensity to find the means of spilling or leaking. If they carried too much water on the carts it would slow their progress. But if too little was loaded and the column was delayed by a sandstorm, or enemy action, then it would run out and the men would suffer the agonies of thirst that desert conditions swiftly made so acute.