There was a chorus of groans and swearing that made Macro smile, then the men stood up and raised their yokes as the optios strode down the line bawling out those who responded too slowly to the order. Each century formed up and stood ready, waiting for the order to resume the march. Macro waited until they were still and silent, then bellowed down the line, ‘Column! Advance!’

They shuffled forward, gradually picking up the pace. Macro led them a short distance beyond the belt of palms before leaving the road to march round a shrine and then turning back towards the camp, passing down the tail of the column and the covered carts carrying those who had collapsed on the outward leg. Midday passed and the afternoon breeze picked up, bringing with it the lightest of dust from the desert. The grit caught in the men’s mouths and their eyes, adding to the discomfort of the scorching heat that beat down on them. Worse still, the glare made the road ahead shimmer as if a perpetually receding sheet of water lay before them, tormenting them with the prospect of assuaging their growing thirst.

More men fell out of line, and this time fewer of them could be coaxed back into place by the blows of the optios and were left for the carts to pick up. Cato had slowed a little so that he was now marching amid the other officers, a short distance behind Macro. Most of the centurions were coping with the strain of the march well enough, some struggled, and the last of those officers who had been avoiding the drills soon gave in and slumped to the side of the road to await the carts.

Cato had never known such heat, not even when he and Macro had crossed the Syrian desert to Palmyra. His tunic, encased in armour, felt tight against him, constricting his breath as he laboured under the weight of the yoke and the broad shield hanging from it. His feet and legs felt leaden and each step became an effort of will. They passed back through the villages near Diospolis Magna and out came the noisy clusters of children again. This time they were met with silence as the soldiers ignored them, unwilling to waste any breath telling the children to go away.

In the middle of the afternoon Cato looked up to see the pylons and standards of Karnak wavering in the distance. His heart lifted at the sight, and he gritted his teeth and looked down again, concentrating on each step in turn, not wanting to look up and see the temples seeming as far off as ever.

‘Step up the pace, lads!’ Macro called out cheerfully. ‘We’re almost home. Let’s show the other cohorts how real soldiers march!’

His words were met with silence and Macro paused and turned back to face them. ‘What’s the matter with you? Are we happy?’