The court of inquiry is just about to break up, leaving the matter for further advisement, when the news comes from Rome that the Emperor's Spanish and German troops, who have not been paid for months, have run wild through the Holy City paying themselves, plundering the treasuries and stoning the artworks. Dressed satirically in stolen vestments, they have raped the wives and virgins of Rome. They have tumbled to the ground statues and nuns, and smashed their heads on the pavements. A common soldier has stolen the head of the lance that opened the side of Christ, and has attached it to the shaft of his own murderous weapon. His comrades have torn up antique tombs and tipped out the human dust, to blow away in the wind. The Tiber brims with fresh bodies, the stabbed and the strangled bobbing against the shore. The most grievous news is that the Pope is taken prisoner. As the young Emperor, Charles, is nominally in charge of these troops, and presumably will assert his authority and take advantage of the situation, King Henry's matrimonial cause is set back. Charles is the nephew of Queen Katherine, and while he is in the Emperor's hands, Pope Clement is not likely to look favourably on any appeals passed up from the legate in England.

Thomas More says that the imperial troops, for their enjoyment, are roasting live babies on spits. Oh, he would! says Thomas Cromwell. Listen, soldiers don't do that. They're too busy carrying away everything they can turn into ready money.

Under his clothes, it is well known, More wears a jerkin of horsehair. He beats himself with a small scourge, of the type used by some religious orders. What lodges in his mind, Thomas Cromwell's, is that somebody makes these instruments of daily torture. Someone combs the horsehair into coarse tufts, knots them and chops the blunt ends, knowing that their purpose is to snap off under the skin and irritate it into weeping sores. Is it monks who make them, knotting and snipping in a fury of righteousness, chuckling at the thought of the pain they will cause to persons unknown? Are simple villagers paid – how, by the dozen? – for making flails with waxed knots? Does it keep farm workers busy during the slow winter months? When the money for their honest labour is put into their hands, do the makers think of the hands that will pick up the product?

We don't have to invite pain in, he thinks. It's waiting for us: sooner rather than later. Ask the virgins of Rome.

He thinks, also, that people ought to be found better jobs.

Let us, says the cardinal at this point, take a step back from the situation. He suffers some genuine alarm; it has always been clear to him that one of the secrets of stability in Europe is to have the papacy independent, and in the clutches of neither France nor the Emperor. But his nimble mind is already skipping towards some advantage for Henry.

Suppose, he says – for in this emergency, it will be to me that Pope Clement looks to hold Christendom together – suppose I were to cross the Channel, stop off in Calais to reassure our people there and suppress any unhelpful rumours, then travel into France and conduct face-to-face talks with their king, then progress to Avignon, where they know how to host a papal court, and where the butchers and the bakers, the candlestick-makers and the keepers of lodgings and indeed the whores have lived in hope these many years. I would invite the cardinals to meet me, and set up a council, so that the business of church government could be carried on while His Holiness is suffering the Emperor's hospitality. If the business brought before this council were to include the king's private matter, would we be justified in keeping so Christian a monarch waiting on the resolution of military events in Italy? Might we not rule? It ought not to be beyond the wit of men or angels to send a message to Pope Clement, even in captivity, and the same men or angels will bring a message back – surely endorsing our ruling, for we will have heard the full facts. And when, of course, in due time – and how we all look for that day – Pope Clement is restored to perfect liberty, he will be so grateful for the good order kept in his absence that any little matter of signatures or seals will be a formality. Voilà – the King of England will be a bachelor.

Before this can happen the king has to talk to Katherine; he can't always be hunting somewhere else, while she waits for him, patient, implacable, his place set for supper in her private apartments. It is June, 1527; well barbered and curled, tall and still trim from certain angles, and wearing white silk, the king makes his way to his wife's apartments. He moves in a perfumed cloud made of the essence of roses: as if he owns all the roses, owns all the summer nights.

His voice is low, gentle, persuasive, and full of regret. If he were free, he says, if there were no impediment, it is she, above all women, that he would choose for his wife. The lack of sons wouldn't matter; God's will be done. He would like nothing better than to marry her all over again; lawfully, this time. But there it is: it can't be managed. She was his brother's wife. Their union has offended divine law.

You can hear what Katherine says. That wreck of a body, held together by lacing and stays, encloses a voice that you can hear as far as Calais: it resounds from here to Paris, from here to Madrid, to Rome. She is standing on her status, she is standing on her rights; the windows are rattled, from here to Constantinople.

What a woman she is, Thomas Cromwell remarks in Spanish: to no one in particular.

By mid-July the cardinal is making his preparations for the voyage across the Narrow Sea. The warm weather has brought sweating sickness to London, and the city is emptying. A few have gone down already and many more are imagining they have it, complaining of headaches and pains in their limbs. The gossip in the shops is all about pills and infusions, and friars in the streets are doing a lucrative trade in holy medals. This plague came to us in the year 1485, with the armies that brought us the first Henry Tudor. Now every few years it fills the graveyards. It kills in a day. Merry at breakfast, they say: dead by noon.

So the cardinal is relieved to be quitting the city, though he cannot embark without the entourage appropriate for a prince of the church. He must persuade King Fran?ois of the efforts he should make, in Italy, to free Pope Clement by military action; he must assure Fran?ois of the King of England's amity and assistance, but without committing any troops or funds. If God gives him a following wind, he will bring back not only an annulment, but a treaty of mutual aid between England and France, one which will make the young Emperor's large jaw quiver, and draw a tear from his narrow Habsburg eye.