‘The whole of France is ours by right,’ my husband says, looking jealously at the green lands that lead down to the Mediterranean sea. ‘And we will have it. We will have it. I shall win it for God and King Harry.’

He leans forwards. ‘Look, we are advancing,’ he says, showing me the little flags of St George for England spreading over the east of France. ‘And if the Duke of Burgundy will remain true, and a good ally, we can win back our lands in Maine. If the Dauphin is fool enough to attack the duke – and I think that he is – and if I can persuade the duke that we both fight at once . . .’ He breaks off as he sees I am looking upwards. ‘Oh, those are my planets,’ he says, as if he owns the night skies quite as much as he does France.

Suspended from criss-crossing wooden beams is a series of beautiful silver spheres, some of them ringed with silver haloes, some with other tiny balls floating nearby. It is such a pretty sight that I forget all about the map and the flags of campaigns and clasp my hands together. ‘Oh, how pretty! What is this?’

Woodville the squire gives a little choke of laughter.

‘It is not for amusement,’ my husband says dourly. Then he nods at one of the clerks. ‘Oh well – show the duchess the skies at her birth.’

The young man steps forwards. ‘Excuse me, Your Grace, when were you born?’

I flush. Like almost all girls I don’t know the date of my birth: my parents did not trouble to record the day and the time. I only know the year and the season, and I only know the season because my mother had a great desire for asparagus when she was carrying me and swears that she ate it too green and her belly-ache brought on my birth. ‘Spring 1416,’ I say. ‘Perhaps May?’

He pulls out a scroll from the library and spreads it across the tall desk. He looks at it carefully, then reaches out and pulls one of the levers, then another, then another. To my absolute delight the balls, with their haloes, and the little balls spinning, descend from the rafters, and move gently around until they are positioned, swaying slightly, in the places in heaven that they held at the moment of my birth. There is a sweet tinkling noise, and I see that the spheres have tiny silver bells attached to the strings that move them, so they play as they take their places.

‘I can predict where the planets will be before I start a battle,’ my husband says. ‘I only launch a campaign when they tell me the stars are propitious. But it takes hours to calculate on paper, and it is easy to make a mistake. Here we have built a mechanism as beautiful and as regular as God made when He put the stars in the sky and set them in motion. I have made a machine like the workings of God Himself.’