Macro snatched up one of the weapons stacked to the rear of the tower and stepped up to the parapet. He aimed with his left arm as he drew his right back, bicep powerfully bunched in readiness. Macro’s eyes narrowed fractionally, and then he hurled his throwing arm forward with an animal grunt of effort. The javelin flew down in a flat trajectory, and passed harmlessly by the native leader who had just taken a step to one side to shout encouragement to his warriors, wholly oblivious to the weapon that slashed through the space where he had been standing an instant before.

‘Bastard!’ Macro yelled in frustration. ‘Wait. I’ll have you . . .’

He turned away to fetch another weapon but Cato caught his arm. ‘Too late for that. Look!’

The first of the enemy warriors had reached the top of the ladder and was battling with a pair of legionaries blocking his way. The native carried a long-handled axe in his right hand which he swung wildly as he edged himself up another step. The heavy blade of the axe battered the shield of one of the defenders, splintering the surface and driving the man back. His comrade instinctively retreated a step at the sight of the fierce weapon slicing through the chilly air. At once the warrior threw a leg over the palisade and nimbly dropped on to the walkway. He slashed right and left with his axe, the head crashing off the heavy shields of the legionaries, holding them off, while a second man clambered to the top of the ladder. Further along the wall more ladders were being raised and the defenders were fully committed as they struggled to thrust the ladders back, and if that failed, desperately striking at the heads and shoulders of the men scaling the ladders. Cato saw Quertus, fifty paces away, hacking the arm off an enemy trying to clamber over the palisade. The Thracian let out a triumphant roar as the warrior fell off the ladder, and then he turned to look for another opponent.

Cato swallowed nervously and drew out his sword. ‘Macro, on me! We’re needed on the wall.’