I said nothing for a while. The old Arthur, the Arthur who had been my friend before that night in Isis’s temple, would never have spoken those words for they were not true. No man would cede British land to the Sais. Arthur was lying in the hope that Aelle would believe the lie, and in a few years Arthur would break the promise and attack Aelle. I knew that, but I knew better than to challenge the lie, for then I could not pretend to believe in it myself. Instead I reminded Arthur of an ancient oath that had been buried on a stone beside a far-off tree. ‘You’ve sworn to kill Aelle,’ I reminded him. ‘Is that oath forgotten?’

‘I care for no oaths now,’ he said coldly, then the temper broke through. ‘And why should I? Does anyone keep their oaths to me?’

‘I do, Lord.’

‘Then obey me, Derfel,’ he said curtly, ‘and go to Aelle.’

I had known that demand was coming. I did not answer at first, but watched Issa shove his youngsters into a shaky-looking shield wall. Then I turned to Arthur. ‘I thought Aelle had promised death to your emissaries?’

Arthur did not look at me. Instead he gazed at that far green mound. ‘The old men say it will be a hard winter this year,’ he said, ‘and I want Aelle’s answer before the snows come.’

‘Yes, Lord,’ I said.

He must have heard the unhappiness in my voice for he turned on me again. ‘Aelle will not kill his own son.’

‘We must hope not, Lord,’ I said blandly.

‘So go to him, Derfel,’ Arthur said. For all he knew he had just condemned me to death, but he showed no regret. He stood and brushed the scraps of grass from his white cloak. ‘If we can just beat Cerdic next spring, Derfel, then we can remake Britain.’ ‘Yes, Lord,’ I said. He made it all sound so simple: just beat the Saxons, then remake Britain. I reflected that it had always been thus; one last great task, then joy would always follow. Somehow it never did, but now, in desperation and to give us one last chance, I must travel to see my father.

I AM A SAXON. My Saxon mother, Erce, while she was still pregnant, was taken captive by Uther and made a slave and I was born soon after. I was taken from my mother as a small child, but not before I had learned the Saxon tongue. Later, much later, on the very eve of Lancelot’s rebellion, I found my mother and learned that my father was Aelle.

My blood then is pure Saxon, and half royal at that, though because I was raised among the Britons I feel no kinship with the Sais. To me, as to Arthur or to any other free-born Briton, the Sais are a plague carried to us across the Eastern Sea.