Cato dropped to the man’s side and felt his way down the calf, over the boot, until his fingers brushed the iron prongs.There was no time to spare, and Cato grasped the spikes and wrenched the caltrop from the man’s boot. Petronius cried out in surprise and pain and at once there was a shout from the men chasing them as they made for the sound.

‘Shit,’ Cato muttered. ‘Get him up. We’re in line with the passage. Head for the wall, and keep those lights in line.’

Cato counted seven men passing him and waited a moment for the rest, but then he heard the enemy shouting close by and he turned to follow his men.Their pursuers were closer than he thought and several figures appeared from the gloom, and shouted to the others the moment they caught sight of Cato making off from them, as fast as he dared, through the fort’s outer defences. With their prey in view the enemy ran heedlessly towards Cato, straight across the defences at an angle to the passage the Romans were doing their best to follow. Cato continued for a few more steps before he turned and crouched low, ready to defend himself. There was a shrill cry as the nearest man tumbled over, and clutched at his foot. Then another man went down, and a third stumbled into one of the shallow pits. Only one of them made it as far as Cato and launched himself at the Roman, thrusting a long-bladed sword at the centre of the centurion’s body. Cato just had time to sweep his sword over and counter the blow, then the man slashed horizontally, forcing him to drop on one knee and duck his head. As the blade swished overhead Cato slashed out with his own sword at knee height and felt it cut into the joint with a wet, jarring thud that severed tendons and smashed bones so that the enemy fell sprawling on his back, crying out. Cato left him, and shuffled to his side until the lights were aligned. Then he set off again.

Behind him the Judaeans had realised the danger and stopped short of the outer defences. Cato smiled to himself. His plan had worked as he had hoped. All that remained was to gain the wall and move along it to the sally port and then the night’s raid was over. Something thudded into the sand beside him. Then again, just behind his boot so that he felt the spray of grit against his calf. Frustrated by the defences, the enemy were throwing stones after the Romans.

Cato hunched his head down and quickened his pace to a slow trot, fearing that at any moment he would feel the stab of iron bursting through the soles of his boots, leaving him crippled and helpless. Suddenly he was upon his own men, and he drew up sharply, almost stumbling over them.