I suspect, but have never asked, that Igraine used a charm to bring the disease to her rival. My Queen might call herself a Christian, but Christianity is not a religion that offers the solace of revenge to its adherents. For that you must go to the old women who know which herbs to pluck and what charms to say under a waning moon.

‘You forgave Brochvael,’ I agreed, ‘but would Brochvael have forgiven you?’

She shuddered. ‘Of course not! He’d have burned me alive, but that’s the law.’

‘Arthur could have burned Guinevere,’ I said, ‘and there were plenty of men who advised him to do just that, but he did love her, he loved her passionately, and that was why he could neither kill her nor forgive her. Not at first, anyway.’

‘Then he was a fool!’ Igraine said. She is very young and has the glorious certainty of the young.

‘He was very proud,’ I said, and maybe that did make Arthur a fool, but so it did the rest of us. I paused, thinking. ‘He wanted many things,’ I went on, ‘he wanted a free Britain and the Saxons defeated, but in his soul he wanted Guinevere’s constant reassurance that he was a good man. And when she slept with Lancelot it proved to Arthur that he was the lesser man. It wasn’t true, of course, but it hurt him. How it hurt. I have never seen a man so hurt. She tore his heart.’

‘So he imprisoned her?’ Igraine asked me.

‘He imprisoned her,’ I said, and remembered how I had been forced to take Guinevere to the shrine of the Holy Thorn at Ynys Wydryn where Arthur’s sister, Morgan, became her jailer. There was never any affection between Guinevere and Morgan. One was a pagan, the other a Christian, and the day I locked Guinevere into the shrine’s compound was one of the few times I ever saw her weep. ‘She will stay there,’ Arthur told me, ‘till the day she dies.’