‘Fate is inexorable,’ I said and, when he looked quizzically at me, I smiled. ‘That was one of Merlin’s favourite sayings. That and “Don’t be absurd, Derfel.” I was always absurd to him.’

‘I’m sure you weren’t,’ he said loyally.

‘We all were. Except perhaps Nimue and Morgan. The rest of us simply weren’t clever enough. Your mother, maybe, but she and he were never really friends.’

‘I wish I’d known him better.’

‘When you’re old, Gwydre,’ I said, ‘you can still tell men that you met Merlin.’

‘No one will believe me.’

‘No, they probably won’t,’ I said. ‘And by the time you’re old they’ll have invented new stories-about him. And about your father too.’ I tossed a scrap of shell down the face of the fort. From far off across the water I could hear the strong sound of men chanting and knew I listened to the launching of Prydwen. Not long now, I told myself, not long now. ‘Maybe no one will ever know the truth,’ I said to Gwydre.

‘The truth?’

‘About your father,’ I said, ‘or about Merlin.’ Already there were songs that gave the credit for Mynydd Baddon to Meurig, of all people, and many songs that extolled Lancelot above Arthur. I looked around for Taliesin and wondered if he would correct those songs. That morning the bard had told us that he had no intention of crossing the sea with us, but would walk back to Siluria or Powys, and I think Taliesin had only come with us that far so that he could talk with Arthur and thus learn from him the tale of his life. Or perhaps Taliesin had seen the future and had come to watch it unfold, but whatever his reasons, the bard was talking with Arthur now, but Arthur suddenly left Taliesin’s side and hurried towards the shore of the sea-lake. He stood there for a long while, peering northwards. Then, suddenly, he turned and ran to the nearest high dune. He clambered up its face, then turned and stared northwards again.

‘Derfel!’ Arthur called, ‘Derfel!’ I slithered down the fort’s face and hurried over the sand and up the dune’s flank. ‘What do you see?’ Arthur asked me.

I stared northwards across the glittering sea-lake. I could see Prydwen halfway down its slip, and I could see the fires where salt was panned and the daily catches were smoked, and I could see some fishermen’s nets hanging from spars planted in the sand, and then I saw the horsemen.

Sunlight glittered off a spear point, then another, and suddenly I could see a score of men, maybe more, pounding along a road that led well inland of the sea-lake’s shore. ‘Hide!’ Arthur shouted, and we slid down the dune, snatched up Seren and Arthur-bach, and crouched like guilty things inside the fort’s crumbling ramparts.

‘They’ll have seen us, Lord,’ I said.

‘Maybe not.’

‘How many men?’ Culhwch asked.