Walking underneath the steeple of St Paul’s, she looks up, still scarcely believing anything can be so tall, or that the vast rose window set in the eastern end of the church can be so lavish. Thomas stares open-mouthed, tripping himself on the road. But soon they turn and pass along a street where the smell of rotten meat rises from the stones and the friars give way to butchers’ boys and husbandmen. They queue again to pass through the Newgate, and then they are outside the city walls again, among priories and abbeys and smallholdings as they follow the road up the hill past various inns. The smell of cows is everywhere and the road is thick with their dung.

Soon they reach some worn-out pasture around a pond where once again they set up camp among the pigs and dogs and piles of every kind of filth. Geoffrey has to buy the wood for their fire from a local farmer and they eke it out with discarded rushes that burn without a flame or heat and send a column of dense grey smoke into the damp afternoon air.

‘What a shithole,’ Dafydd says.

Thomas finds his reed and a bottle of ink, and then unstraps the pardoner’s ledger and begins copying the design of the rose window of St Paul’s from memory in a margin. Katherine sits and watches. It is mesmerising, seeing his reed shape and shade the paper.

After a moment Red John joins them and is alarmed.

‘What’re they?’ he asks, pointing at the names. He looks at them as if the words may have magical powers, as if they are a chant, or are somehow threatening.

‘The names of Englishmen stationed in Rouen in 1441,’ Thomas tells him, and he runs his finger along the crudely rendered letters. ‘Look. There is the Duke of York mentioned, and his retinue.’

Red John is amazed.

‘I thought it was just the Bible in words,’ he says.

‘No,’ Thomas tells him. ‘It is a record of men and their movements in France. It says the Duke spent the summer of 1441 in a place called Pontoise.’

‘Where’s that?’

‘I don’t know.’

Red John points to another column.

‘And what are they?’

‘The names of men who stayed in Rouen that year.’

‘Read them out.’

‘William Hyde. Hugh Smyth. John Rygelyn. William Darset. Robert Philip. Nicholas Blaybourne.’

The list is long. Who are these men? Katherine wonders again. Thomas has said they are long-dead soldiers, so why was the record of their movement important to the pardoner?

‘Can you write as well?’ Red John asks.

Thomas nods, and he writes two words.

‘Look,’ he says. ‘That is your name.’