Cato did a quick calculation. ‘Four hundred and twenty, or so. Enough to hold the wall either side of the main gate.’

‘Barely,’ said Quertus. ‘Once we start losing men, we’ll be stretched thin.’

Cato shot him a withering look. ‘Obviously. We’ll deal with that if the time comes. Meanwhile, there’s every reason to think we can hold out. We can make our food last for ten more days at least. More, if we cut the rations of the prisoners. The real problem is going to be the horses. With the loss of the haystacks, they’ll have to make do with whatever feed we have inside the fort. Quertus?’

The Thracian officer scratched his jaw. ‘There’s a standing provision of three days in the stables.’

‘Three days?’ Cato thought briefly. ‘Very well, keep one of the squadrons on full feed. The rest of the mounts go on half feed. After two days, cut it to a quarter. If we’re still under siege when the supply is exhausted we’ll have to start slaughtering them. At least that’ll help with the rations for the men. Fresh meat will give them heart.’

Quertus’s expression darkened and his officers stirred and exchanged angry glances. Quertus rose to his feet.

‘No one is killing my horses. Not without my say-so.’

Cato casually clasped his hands behind his back so that no one might see the tense trembling of his fingers. The Thracian had challenged him in front of all the officers. Now was the moment to stand his ground, yet he was filled with fear that he had insufficient authority to compel Quertus and the officers of the auxiliary cohort to bow to his will. He forced himself to speak slowly, clearly and forcefully.

‘I have tolerated your insubordinate manner for long enough, Centurion Quertus. The next time you address me in such a fashion I will have you arrested, regardless of the need for every man I can scrape together to defend the fort. It is because of you that every one of us in this room is in danger . . . Now, if I give the order to start slaughtering the horses then it will be done at once and without question, starting with your horse. Is that understood?’

There was a unbearable stillness in the room. Cato stared at his subordinate without blinking. For his part, the Thracian glowered, then at length gritted his teeth and nodded, before slowly easing himself back down on to his bench.