Tullio inspected him closely. ‘Very well. Stay close to me or Annius; it’s likely to be a long night. And keep these people under control.’ Then he turned away, dismissing Brigonius and his party.

A junior officer ran up. ‘Sir, we’re under attack!’

‘Well, I can see that,’ Tullio snapped. He drew his stabbing sword and turned to face the north. ‘Perhaps those northerners are taking their chance before the Wall is built. Get me a signaller and tell him—’

‘Sir.’ The officer, no older than twenty-five, was distressed, out of his depth. ‘They aren’t coming from the north.’

‘Then where?’

‘From the south, sir. The south!’

Tullio gaped. ‘The south? Which side of this cursed Wall are the barbarians supposed to be on? And how did they set fire to my camp?’

‘I can answer that, sir.’ A tough-looking centurion approached. His face was streaked with ash, and he carried something in his hand, something that dangled and dripped a dark fluid. ‘He was inside the camp. He had business here; he’d been here before. We’d no reason to suspect him. But he was carrying a bottle of oil which he lit and—’

‘Who, man? Who did this?’

The centurion glared at Brigonius. ‘This is yours, I believe.’ He raised his arm. The thing in his hand was a human head, severed at the neck, from which blood still oozed. The face was obscured by a thick black beard. The centurion dumped the wet thing on the floor.

Brigonius flinched but stood his ground, while Lepidina cowered behind him. ‘Matto,’ Brigonius breathed. ‘Oh, you fool.’

Tullio glared. ‘Recriminations later. For now let’s get control of the situation. You,’ he told the centurion. ‘Take charge of what’s going on inside the camp. Put that fire out before it does any more damage.’ The centurion ran off. ‘Annius, you come with me. What are those signallers doing up in that tower, sucking each other off? I need to find out what’s happening in the country ...’ He stalked off, bristling, angry, competent.

Karus was staring at the severed head. ‘I knew this man.’

‘He was my cousin,’ Brigonius said grimly. ‘He worked for me, at the quarry.’

‘What was in his mind, Brigonius? He must have known he could not survive a lone attack on a Roman camp.’

‘But death didn’t matter to him,’ Xander said quietly. ‘The Romans have encountered such suicide killers before - and know they are hard to deal with. As Tacitus has written, “The man who is prepared to die will always be your master.”’