'Have faith, Harry,' Geoffrey said with good humour. 'Have patience! It has been a long haul, but just a little further. This chap de Santangel, who Colon is meeting today, is more businesslike than most courtiers.' A wealthy Aragonese, Luis de Santangel's family had served Fernando's ancestors for centuries as merchants and lawyers. Now de Santangel was treasurer of the Holy Brotherhood, the monarchs' religious police. Geoffrey said, 'De Santangel is a man of money, not of God. He will see Colon's plan as a good business proposition, and I am confident he will back our case. You'd get on with him, Harry.' He grinned. 'Two men of business together, carving up the future! I can see it now.'

Harry wasn't in the mood to be teased. 'But Grace Bigod is here at the court. Hovering around that monster Ferron, damn his cold heart. Ferron longs for war, you know, and so does she. I think they've both gone mad.'

Geoffrey shrugged. 'Grace must continue. She has invested her whole life in this project, even passing up her chance of children and grandchildren. But whatever Grace and Ferron do or say, it is a critical time.

'The monarchs' heads are full of fantasies. Isabel dreams of exploration. And on the other hand Fernando really believes, I think, that he is the Hidden One, the new King David who will return the Ark of the Covenant to the City of David, thus heralding the Second Coming of Christ, and the kingdom of God upon the earth. And so on! Thus the monarchs are predisposed to be swayed either way – west with Colon to find a new world, or east with the Engines of God to continue the logic of their Reconquest.

'This is the time. The war against the Muslims is almost won. Soon, for a brief moment, the souls of the monarchs will be fluid, their purposes fulfilled, their dreams unlocked. And in this moment the future must be fixed. It is now or never for Colon, and the rest of us – perhaps the whole world.'

Harry felt he had already burned up too many years of his working life on this extraordinary project. 'Let's hope that we really are reaching the end of this long game, Geoffrey, one way or another.'

The friar nodded. 'Yes. But, remember, Harry, the true game of the future is only about to begin.'

And at that moment Harry saw Abdul Ibn Ibrahim walking towards them. He was carrying a small wooden box.

Geoffrey rushed to him and clasped his arms. 'Abdul! I didn't know you were here. I haven't seen you since that terrible day in Seville. What became of you?'

Abdul's face was stony. 'I was forced to leave Seville, of course. I returned to Granada, where I went back to the emir's court. Now I find myself working on the finer points of our capitulation treaty.'

Harry was as glad to see Abdul as Geoffrey was. But he could see how grim his mood was. 'What's wrong, Abdul? You know I'll always be grateful to you for having saved Agnes from Ferron.'

Abdul sighed. 'But it is Ferron who has sent me here today.'

'Ferron did?'

'He sought me out. And he gave me this, to present to you.' He handed Harry the box.

Harry took it. It was finely made of cedarwood, an expensive gift.

Abdul said, 'Ferron's message is this. You must not support your champion any more, Harry. When Colon presents his case you must speak out against the arguments you have helped him develop. Otherwise you must stay as silent as your sister.'

Harry was confused, but frightened. 'My sister's safe in England. And she's never been silent.'

Abdul said nothing.

Geoffrey touched Harry's shoulder. 'Open the box, Harry.'

The lid lifted easily, on oiled hinges. Inside was a glass vial, which contained a slab of meat, pickled in some preserving liquid. It took Harry long heartbeats to recognise what it was, from the bloody stump, the shape of the tip. It was a human tongue, severed at the root. In the lid of the box a note was tucked. Harry took this and unfolded it, and read: 'AGNES WOOLER.'

'He took her back,' Geoffrey raged. 'He took her back!'

In the monarchs' audience chamber expensive tapestries hung from the walls, showing such scenes as the Virgin Mary hovering, ethereal, over crusaders who stormed the walls of Jerusalem. And the wooden floor was covered with rich Persian carpets, a gift from Boabdil in Granada to his effective masters. This chamber, at the heart of Santa Fe, was grander than any room Harry had ever been in, even if it was just a mock-up of wood and waxed cloth. And it was full of courtiers. They reminded Harry of exotic birds, preening and gossiping, curious about the latest trial of a favourite of the Queen.

They were curious because here, on benches before a throne-like chair, opposing factions prepared to debate once again the matter of Cristobal Colon.

The throne was occupied today by Luis de Santangel. A portly, sensible-looking man of perhaps forty, dressed expensively, he looked what he was: heavy with money, and an influence at the court. Even if he approved Colon's proposal it would not be the final verdict, which as always lay with the monarchs. But his word carried a good deal of weight.

Harry, Geoffrey Cotesford and Abdul Ibrahim were here under the sponsorship of Antonio de Marchena, the friar from the monastery of La Rabida at Palos who had supported Colon's dream of sailing the Ocean Sea since he had first come to Spain.

Opposing them was Hernando de Talavera, once Isabel's confessor and still the court's principal theologian, and his party of sea captains, geographers and astronomers, and a few clerics. While de Marchena had always supported Colon, Talavera had opposed his case just as steadfastly since he had first presented it six long years ago. Over the years, as Colon refused to give up and disappear, Talavera had grown steadily more exasperated, and was now quite determined Colon would never get his ships.

And, sitting in the front row of courtiers, there was Diego Ferron, who campaigned for Colon to become, not an admiral of the Ocean Sea, but a general of the final war with Islam, leading forces equipped with Grace's Engines of God. Ferron had Moorish attendants with him: a slim, dark woman wearing a jewelled veil, and a servant girl who sat silently at his feet, face covered by her veil, even her eyes invisible. It seemed strange to Harry that this man who was arguing for the violent destruction of Islam should have Muslim servants, but these were the last days of Granada, and Boabdil, cornered and compromised, was lavish in his gifts of people as well as objects to the court of the monarchs.

Harry stared at Ferron, but he would not look back. After Agnes's destruction of the engines there was only hatred between the two camps, he thought, a hatred that could surely only end with the destruction of one or other of them – and, perhaps, of Agnes.

Now a shiver of excitement ran around the crowded room. Harry looked around.

A man strode boldly into the room. He was dressed in a long black robe like a monk's habit, and he carried a bundle of maps and books under his arm. He was tall, and his swept-back hair was almost pure white, with at the temples traces of a vanishing russet red. His brow was broad, and his imposing face was dominated by a strong nose; his skin was somewhat freckled, a sea-farer's face, and his eyes were grey-green – the colour of the ocean, Harry thought. He looked like a Roman senator, a revenant from a grander age than this. Yet there was anxiety in his sea-green eyes as he fumbled to lay out his charts and books on a table before de Santangel. Some of the courtiers even laughed. And, Harry thought, looking at that shock of white hair, though he was only just forty years old he was already growing old in the pursuit of his single dream.

In all the long years Harry had been tracking his career, this was the first time he had seen the man in the flesh. This was Cristobal Colon, Christophorus Columbus, a man who seemed to Harry to have been made flesh from the flimsy fragments of prophecies and augurs written down centuries before he had been born. A man about whom history pivoted.