They reached the bank about twenty paces from the bridge and stopped. Ferox bent down to pick up a stone, hefted it and then lobbed high, hearing a splash when it landed. There was little ice left now. For a while he waited, for he must give Vepoc and the others their chance in case they wanted to take it. His own tribe were raised to cherish silence, so he did not feel uncomfortable, although the rare occasions when Brigantes were silent – and awake – were strange.

‘Blood calls for blood,’ Vepoc said eventually.

‘Aye.’

Vepoc was about Ferox’s age, and had served in the royal ala, rising to the rank of duplicarius, a ‘double-pay man’ second only to the decurion in each turma. There were stories that before that he had been a famous warrior and raider, which in truth meant much the same thing. He had killed warriors from other clans and tribes – and Romans – and lived to tell of it, just as he had lived through the hardships of the mines and kept his pride and his strength.

‘Just as a wrong calls for vengeance,’ he said.

Ferox did not know whether Vepoc spoke of the killing of Festus, or was referring to Aviragus. He had certainly fought for the king, and been considered dangerous enough to be sentenced.

‘If Andoco was a legionary,’ Ferox began, ‘then he would be flogged and beheaded, his head placed on a stake and the rest of his corpse denied proper burial. That is the way of the army, as you know.’

‘We are not Romans.’

‘Yet you are here.’ Ferox leaned over and found another pebble. ‘And you are oath sworn to serve the Lord Trajan.’

‘If you kill him then I must kill you.’ Vepoc did not mean the emperor. ‘The centurion was a fool.’ He had his hand resting on the pommel of his sword. He did not move, and was not tense or giving any other sign that he was about to spring.

Ferox tossed the stone up and caught it. ‘There are many fools in the world, and plenty of them are chieftains and lords.’

‘Andoco is my brother. Oath or not, I must avenge him, and so must our cousins.’

‘I know. The Silures understand the calls of blood.’ There was no harm in speaking as one of his own folk, and not as the citizen and centurion.

Vepoc sniffed in contempt. ‘Silures know nothing of honour.’

‘Yet any folk who have wronged us know how much we are driven to vengeance.’ Ferox reached back and threw the stone as far out as he could. There was no sound, so either he had reached a patch of ice or the far bank. ‘The choice is yours.’ He spread his arms wide and turned to face the warrior. If Vepoc wanted to kill him he had a good chance of drawing his sword and striking before Ferox could answer.

Vepoc did not move and was silent for a long while.