Twelve of us rode. Arthur, Galahad, Culhwch, Derfel and Issa were the Dumnonians, the others were Cuneglas and his followers. Today, where the story is still told, children are taught that Arthur, Galahad and I were the three ravagers of Britain, but there were twelve riders in that night of the dead. We had no body armour, just our shields, but every man carried a spear and a sword.

Folk shrank to the sides of the firelit street as we rode towards Durnovaria’s southern gate. The gate was open, as it was left open every Samain Eve to give the dead access to the town. We ducked under the gate beams then galloped south and west between fields filled with people who stared enthralled at the boiling mix of flame and smoke that streamed from the hill’s summit.

Arthur set a terrifying pace and I clung to my saddle pommel, fearful of being thrown. Our cloaks streamed behind, our sword scabbards banged up and down, while above us the heavens were filled with smoke and light. I could smell the burning wood and hear the crackle of the flames long before we reached the hill’s slope.

No one tried to stop us as we urged the horses uphill. It was not till we reached the intricate tangle of the gateway maze that any spearmen opposed us. Arthur knew the fortress, because when he and Guinevere had lived in Durnovaria they had often come to its summit in the summertime and he led us unerringly through the twisting passage and it was there that three Black-shields levelled their spears to halt us. Arthur did not hesitate. He rammed his heels back, aimed his own long spear and let Llamrei run. The Blackshields twisted aside, shouting helplessly as the big horses thundered past.

The night was all noise and light now. The noise was of a mighty fire and the splitting of whole trees in the heart of the hungry flames. Smoke shrouded the lights in the sky. There were spearmen shouting at us from the ramparts, but none opposed us as we burst through the inner wall onto Mai Dun’s summit.

And there we were stopped, not by Blackshields, but by a blast of searing heat. I saw Llamrei rear and twist away from the flames, saw Arthur clinging to her mane and saw her eyes flash red with reflected fire. The heat was like a thousand smithy furnaces; a bellowing blast of scorching air that made us all flinch and reel away. I could see nothing inside the flames, for the centre of Merlin’s design was hidden by the seething walls of fire. Arthur kicked Llamrei back towards me. ‘Which way?’ he shouted.

I must have shrugged.

‘How did Merlin get inside?’ Arthur asked.

I made a guess. ‘The far side, Lord.’ The temple was on the eastern side of the fire-maze and I suspected a passage must surely have been left through the outer spirals.