‘But look at the Earl of Warwick. How did he become the Earl of Warwick? He married Anne Beauchamp, Countess of Warwick. So he got the title and the estates through his wife. Why shouldn’t the crown pass so?’

‘Because it’s the crown,’ Walter says.

‘Well, there you have it,’ Sir John says. ‘I don’t suppose the lords are arguing it any more clearly in there.’ He gestures to the hall. ‘But it is a shame,’ he goes on, ‘because on this question men will lose their lives.’

‘Lost ’em before; ’ll lose ’em still.’

Sir John sighs.

‘Thank you, Walter. Of course that’s true. But this will divide families. Brother against brother, father against son. That sort of thing. I hope it does not, of course, but whether or not a man has the right to call himself King of England raises dangerous passions that can only lead to more blood being shed.’

The discussion rumbles on all morning, until Katherine can stand it no longer.

‘I think I’ll take a walk,’ she says.

Thomas joins her. The others stay in the square where Sir John labours his points again and again.

‘Sir John seems better,’ Thomas says.

‘Only because he is out of the range of Fournier,’ she snorts.

Beyond the abbey walls they find a stationer selling a poor selection of books, some of them unbound. These are of little interest to Thomas, but Katherine likes them.

‘It is as if their author will return at any moment to take up his reed and continue the conversation,’ she says.

Not all the books are religious tracts.

‘What is that one there?’ she asks, pointing. It is a series of folded sheets, roughly hacked at the edges, bound with strips of cloth the colour of shoe soles. Thomas unties the cords and opens it, watched by the stationer. It smells of must.

‘Saints,’ Katherine says.

On the very first spread of pages is a startling picture of a man in robes with his finger inserted in another man’s anus.

‘It’s a treatise on fistulae,’ Thomas reads aloud. ‘By a man named John Arderne. He is a barber surgeon of London, it says.’

They study the picture. There are more besides, each as peculiar and gruesome as the first. Thomas flushes.

‘So a fistula can be cured?’ she asks.

‘I think so,’ Thomas says, reading on a little. ‘Though I should not like to see it done.’