The enemy arrived just as the last boat was being loaded. That was the largest boat and it belonged to Balig, my sister’s husband. In it were Arthur, Guinevere, Gwydre, Morwenna and her children, Galahad, Taliesin, Ceinwyn and me, together with Culhwch, his one remaining wife and two of his sons. Arthur’s banner flew from the boat’s high prow and Gwydre’s standard flapped at the stern. We were in high spirits, for we were sailing to give Gwydre his kingdom, but just as Balig was shouting at Hygwydd, Arthur’s servant, to hurry aboard, the enemy came.

Hygwydd was bringing a last bundle from Arthur’s palace and he was only fifty paces from the river bank when he looked behind and saw the horsemen coming from the town gate. He had time to drop the bundle and half draw his sword, but then the horses were on him and a spear took him in the neck.

Balig threw the gangplank overboard, pulled a knife from his belt and slashed the stern mooring line. His Saxon crewman threw off the bow line and our boat drifted out into the current as the horsemen reached the bank. Arthur was standing and staring in horror at the dying Hygwydd, but I was looking towards the amphitheatre where a horde had appeared.

It was not Mordred’s army. This was a swarm of the insane; a scrabbling rush of bent, broken and bitter creatures who surged round the amphitheatre’s stone arches and ran down to the river bank yelping small cries. They were in rags, their hair was wild and their eyes filled with a fanatical rage. It was Nimue’s army of the mad. Most were armed with nothing but sticks, though a few had spears. The horsemen were all armed with spears and shields, and they were not mad. They were fugitives from Diwrnach’s Bloodshields and still wore their ragged black cloaks and carried their blood-darkened shields, and they scattered the mad people as they spurred down the bank to keep pace with us.

Some of the mad went down beneath the horses’ hoofs, but dozens more just plunged into the river and swam clumsily towards our boats. Arthur shouted at the boatmen to let go their anchors, and one by one the heavily laden boats cut themselves free and began to drift. Some of the crews were reluctant to abandon the heavy stones that served as anchors and tried to haul them up, and so the drifting boats crashed into the stationary ones and all the time the desperate, sad, mad things were thrashing clumsily towards us. ‘Spear butts!’ Arthur shouted, and seized his own spear, turned it, and thrust it hard down onto a swimmer’s head.