I staggered behind Gereint into a wide clearing. Beyond the all-enclosing thicket, the ground was rocky and uneven, and the hedge wall stood back in a circle all around. In the centre of the clearing rested a squat stone hut with a steep, high-pitched roof, also of stone. The walls were squared, solid, and without openings of any kind, and the roof was covered with moss – in all a most curious dwelling.

Beside the house stood a stone plinth of the kind the Romans used to erect for their statues and memorials. There was no memorial or statue now, but a heap of broken rubble at the foot of the plinth suggested that once there might have been.

These things I took in first, and only when Gereint spoke did I feel the calming silence of the place. 'It is very peaceful here,' the young warrior said, and even at a whisper his voice seemed to boom like a beaten drum.

Placing a finger to my lips, I warned him against speaking aloud until we could discover whether we were the only visitors. Gereint nodded and took my arm upon his shoulder and we proceeded cautiously towards the dwelling.

We had been drawn to the clearing by the light. Now that we were here, however, there was no light to be found and none to be seen -that is, there appeared no source of illumination: no campfire, no torches, no subtle sunlight shining down from above – yet the stone hut did stand suflused in a softly gleaming radiance very like that of moonlight, and what is more, this gentle gloaming bathed the entire clearing with a fine luminescence that shimmered gently at the edges of my vision. Whenever I looked directly at an object, this ghostly glimmering faded, though the soft glow remained.

Wary with every step, we approached the stone hut, moving slowly along the near side to what we took to be the front. There we found a door both low and narrow, its threshold overgrown with weeds and grass. So small was this entrance that only one could pass at a time, and that one must bow almost to his knees to enter.

Gereint cleared away the growth with a few quick swipes of his blade, then, sword in hand, stooped and entered.

A moment later, his face appeared in the doorway, and he said, 'It is empty, lord. There is no one here.'

With some difficulty and no little pain – for I could no longer bend my injured leg at all, and had to lie down and drag myself through the opening – I joined him within. Gereint raised me to my feet again, and we stood together in a holy place.

'It is some kind of chapel,' Gereint said, his voice filling the stone-walled room.

The same weird light that played in the clearing outside also filled the interior of the single, vaulted room, allowing us to see each detail of the rich ornamentation – for every surface was carved with wonderful designs: intricate knotwork panels and borders, countless triscs and spirals, and hundreds of the elongated, much-entwined shapes of animals and men. I recognized this adornment; it was that which the Celts of old made with such zeal and delight. There were also innumerable crosses carved on the walls and floors, many with odd runelike symbols which I could not read.

The room, unforgiving in its square, spare simplicity, seemed to dance to the rhythm and movement of those wonderful carvings. To stand and gaze upon floor and walls and roof was to inhabit a psalm or a glad song of praise. I filled my eyes with the graceful dance of the room, and felt my spirit rise up within me.

'Truly, this is a sacred place,' I said.

'An ancient place,' Gereint replied. 'Look how – '

'Listen!' I held up my hand to quiet him.

There came the sound of a soft footfall – someone was moving along the wall outside. Gereint made a flattening motion with his hand and silently stepped to the doorway, sword ready.

I stood stock-still, straining into the silence. There came no shouts, no cries of help or alarm. I held my breath and heard only the rapid beating of my own heart. And then -

A quick movement at the door and a dark shape burst into the room, straightened, and became the familiar figure I knew.

'Bors!'

Gereint lowered the blade and fell back; he had been that close to striking.

'Here you are!' Bors cried, lowering the sword in his own hand. 'And here was I thinking I had lost you for good.'

His relief was instantly swallowed in amazement as he beheld the walls and floor. He turned his wondering gaze upon the beautiful carvings, and we joined him in silent admiration. Explanations could wait; a greater mystery commanded our attention.

When he spoke again, it was in a voice humbled with awe. 'It is wonderful.'

'That it is,' I agreed. 'I have never seen the like.'

'It reminds me of those cells the monks make in Armorica. Look here,' he said, moving towards the rear of the chapel, 'the altar still stands, and – '

He broke off so suddenly, I glanced quickly at his face, which now wore an expression of revulsion: lips twisted in a grimace of distaste, eyes narrowed in disgust. With my crooked staff, I struggled across the room to join him. 'Damn them to hell,' he muttered, turning his face away.

Then I saw what he had seen, and turned my face away, too. The sight and smell brought bile to my mouth and I coughed, feeling the burn in my throat as I swallowed it back. 'Desecrated.'

On the altar before us lay the severed genitals of a bull, the members placed atop a pile of human excrement. The bull's bloody horns with bits of the skull, and tail with part of the anus attached, flanked the stinking mound on either side, and the poor animal's tongue, torn out by the root, completed the repugnant arrangement.

'Have you found something?' Gereint hastened to where we stood. I tried to warn him off but was too late, and he pushed in beside Bors.

The young warrior looked at the altar. Clapping a hand to his mouth, he choked and turned swiftly away.

'That is the worst of it,' I said.

'Holy Jesu,' he whispered in a small, wounded voice.

'This is not right,' Bors declared solemnly. 'I will not allow it.'

So saying, he stripped off his cloak and flung it over the obscene display. I thought that he meant merely to cover the desecration, but he had another plan, for he spread the cloak and then gathered up the defiling mass, folding it into the cloth. Holding the bundle at arm's length, he bore it from the chapel, returning a moment later with a double handful of grass in each fist.

Striding to the altar, Bors took to scrubbing the flat stone with the grass. 'I need some water,' he said through clenched teeth.

'Maybe there is a well outside,' said Gereint, darting away.

I leaned, exhausted, against the wall while Bors put the full strength of his arms into the cleansing of the venerable stone. As he worked, a faint green sheen began to gleam where the grass, crushed by its abrasion, left some of its substance.

'See here, Gwalchavad,' Bors called, motioning me nearer. 'What is this?'

I hobbled closer, and only then did Bors notice I was wounded. 'But you are hurt, brother. Forgive me, I should have -'

'I will live, never fear,' I said, waving his apology aside. Indicating the altar, I said, 'What do you make of it?'

'It is a circle, and words, I think.' He pointed to a broken arc of spidery lines which seemed to be etched in the stone. 'But I cannot read the letters.'

'Nor can I,' I told him. 'Perhaps if we could see more of it -' Bors fell to scrubbing again, as if by brute effort he could make the words appear. But for all his muscle, the thin, cracked lines did not mend or improve. 'It is no use, Bors. Whatever is written on that stone is worn away and there is no reading it now.'

Bors ceased rubbing, and stood with knots of grass clenched in his fists. 'I should go see what has become of Gereint,' he said, but his eyes never left the etched surface of the stone.