‘This has been carved from the cliff,’ Martine told me. ‘You can see here the marks of the chisel. It is very old, this chapelle. Christian,’ she said, turning, ‘you must tell the story of Sainte Radegonde. I never can remember it properly.’

Christian shrugged uncomfortably and hurried through an abbreviated version. ‘She was a German, like myself – a princess. In the sixth of centuries her people were destroyed by the Frankish king, Clotaire, who took Radegonde for his bride. She was then eleven years old. But she was not happy with Clotaire, and so she left him and became a nun. She founded, here at Chinon, a small convent.’

I looked around. ‘What, in this spot?’

‘No, not here. The hermit Jean was living here, a holy man. I will explain.’ He frowned a little, trying to collect his thoughts. He was clearly unaccustomed to the role of tour guide. ‘When Radegonde was living at Chinon, there came an order from Clotaire, her former husband, that she should be going south to Poitiers to make a convent, for which he would provide the money. But Radegonde, she was not certain this was good, so she came here to visit Jean the hermit, to ask him what to do.’

‘And what did he tell her?’

A second shrug. ‘He said that this was a good idea, to go to Poitiers. And so Sainte Radegonde went there, as Clotaire wanted, and built in Poitiers a great church. It is there that she is buried.’

There was an altar of sorts at the end wall, a heavy stone table laid with a white lace covering, set in a hollowed niche that glowed with ancient paintings.

‘This mural,’ Martine said, pointing to the flaking pigments, rich blue above a deep wine colour, ‘this is not the oldest here. This one is only seventeenth-century.’

There were fresh flowers on the altar, and a wooden standing crucifix flanked by bronze candlesticks. Beneath the drape of lace, a broken sculpture bore the likeness of a medieval woman lost in meditative rapture, a royal crown upon her head.

‘Is this her?’ I asked, bending for a better look, is this Sainte Radegonde?’

Christian nodded. ‘Yes. And also this,’ he said, showing me a daintier statue that graced a second table in the adjoining painted niche. At the feet of this Radegonde were more cut flowers, and a shallow plate with several coins laid in it. Offerings to the saint, I thought, until Christian set me straight.

‘Those are donations to the Friends of Old Chinon,’ he said. ‘To help with the upkeep of the chapelle.’

Always the practical intruded into the romantic, I reminded myself with a wry smile.

Martine was at my shoulder, pointing. ‘The chapelle, it goes even further into the rock, through there.’ She showed me a smaller iron gate that spread to fill an opening in the rear wall. There were no saints behind this gate, no kind benevolent eyes, only a few feet of visible stone floor and then an inky darkness. ‘There are more caves, and many fine museum items, and an ancient well, from Sainte Radegonde’s time. She must see the well, Christian. Do you have the key?’

But the young German shook his head, expressionless. ‘No, I have not brought it with me. We can show the well to her another time.’

‘But Christian, surely …’

‘I have not brought the key, Martine.’ His tone was firm. ‘I am sorry.’

I wasn’t overly disappointed, myself. The dank smell of stone that rose from behind the iron gate was acrid and unwelcoming. Besides, my roving gaze had just that moment fallen on a painted frieze at the opposite end of the covered aisle.

‘I don’t believe it,’ I said abruptly. ‘There’s John.’

Martine, interrupted in her train of thought, looked at the end wall and frowned. ‘Yes, that is Jean the hermit,’ she said. ‘It is a reproduction of his tomb, you understand. The sleeping statue, it is not as old as—’

‘No, I didn’t mean that,’ I broke in. ‘I meant the fresco higher up, at the back. That’s John Lackland, King of England.’

‘Oh, I see. Yes, you are quite right, that is a painting of the Plantagenets.’ Her face cleared, and she led us across the neatly swept floor to the corner where the painting was. It was only a fragment of a fresco, really, with a fair chunk missing along the bottom edge, but the colours were brilliant and stunningly true.

‘I’ve seen this before,’ I said slowly, admiring the artist’s skill. I remembered it from one of Harry’s books.

Martine, the art expert, assured me it had been much photographed. ‘Many people came to see it thirty years ago, when it was found. It is believed to have been painted when this John came here to marry his queen. That is her there,’ she pointed out, ‘on the horse behind her husband’s. Not the older woman at the back, but the young girl riding in the front.’

Neil came up behind me, closer to the wall, his breath stirring the hair on the top of my head. ‘She looks young to be a queen,’ he commented. ‘And she isn’t wearing a crown, is she? The crown is on the older woman.’

‘That’s Eleanor,’ I told him, absently, my eyes fixed on the vibrant painted figures. ‘Eleanor of Aquitaine. She was John’s mother.’ But I wasn’t looking at the famous queen. I was looking at the lovely tragic girl in front of her, the great dark eyes that gazed towards the future with such hope …

‘It was by luck alone that this survived,’ Martine was saying. ‘Just after it was painted Chinon came to the French king. This John of England, he killed someone, I think, and it was not so nice to have his picture in the church. And so this fresco, it was covered up with plaster. It was not seen again until 1966, when some of the plaster fell down.’