It was a huge relief for Harry to get out of the chaotic confines of the audience chamber and into the clear Spanish air. He still had his sister in his arms. Geoffrey stood by him, panting with shock and fear.

The army camp was in chaos. The attempt on Isabel's life had been like a stick thrust into a beehive. Soldiers ran everywhere. There were screams, and the crack of arquebuses. Muslims, who an hour ago had been able to go about their business unmolested, now ran for their lives. It was a grim irony, Harry thought, that it had been a Muslim who in fact had saved the Christian Queen, and a Christian who had tried to kill her.

'But I don't understand,' he said. 'I don't understand.'

'Evidently Grace didn't know of Ferron's scheme with Agnes,' Geoffrey said grimly. 'Our opponents didn't even trust each other! Grace saw she was losing the argument, Harry. She saw we were winning. And that couldn't be allowed. She was a woman who had come to need her murderous war, the glory of her weapons. She would even impersonate a Muslim, she would murder the greatest Christian queen, in order to win the argument – and to provoke needless slaughter.'

'And Abdul-'

'Abdul, in that flash as the blade descended towards Isabel, saw the opposite. The Moors are already defeated, here in Spain; Boabdil, for all he is despised, is doing a decent job of negotiating a surrender with honour. But if Isabel had been killed Fernando and his soldiers would have vented their fury on Granada. And in the east, the sultans would have responded to such a massacre as they have always threatened to do, beginning with reprisals against the Christians in Jerusalem, and against our holy sites.'

'And then the holy war would have been inevitable.'

'Yes. Abdul saw it all in a flash. He gave his life to save a Christian monarch, and to avert global disaster.'

'We have all spoken of such possibilities,' Harry said. 'But it was Abdul who acted.'

'He was a better man than either of us,' Geoffrey murmured, calming. 'He has saved countless lives, beginning with Isabel's. Perhaps he has saved the future.'

Something in the sky caught Harry's eye. It was like a bird, yet massive, more ungainly, high in the air. And it was spinning, spinning towards the ground, as if it had broken a wing.

'Is that a man? Is that James of Buxton? Are men meant to fly, Geoffrey?'

'If so, not here, not now.'

The fragile contraption, all struts and feathers, tumbled down, out of sight. It didn't seem to matter. Harry held Agnes close, murmuring to her, longing for her to wake from her drugged stupor.

There was much excitement around the harbour of Palos this August morning. The place was crowded with curious Christians, many still wearing their crusader shoulder flashes, and with Jews desperate to flee a country that had rejected them.

Harry and Geoffrey walked a good distance, pushing through the crowds, trying to get a glimpse of the explorers. In the end they climbed a steep slope, just outside the town, from which they could see the harbour and the three ships it cradled.

It was a modest fleet. There were the two caravels, called the Pinta and the Santa Clara, the latter more commonly known as the Nina after its owner, a man called Juan Nino. And there was the one larger carrack called the Santa Maria, but often called La Gallega as it had been built in Galicia. The Santa Maria carried square sails on a foremast and mainmast, and a triangular lateen sail on a mizzenmast at the rear. The Pinta was rigged like the Santa Maria, but the Nina relied on lateen sails. The two caravels especially were graceful, slim little ships.

In these last minutes before they cast off Harry could see the figures of the crew loading their ships, bustling around the decks and the stout castles at prow and stern. The men looked somehow too large for their ships, which were only some fifty or sixty feet long; they were terribly tiny ships to challenge a world ocean. Harry remembered Abdul telling him that the rudders on some Chinese vessels were almost the size of a ship like the Nina.

And yet it was not the Chinese who sailed today, but Cristobal Colon.

'Modest they may be, yes,' Geoffrey said, when Harry voiced these thoughts. 'But look at them, Harry, bristling in the water, full of purpose. Henry the Navigator would be proud to see the day – even if they are Spanish ships sailing from a Spanish port.'

'It's turning out to be quite a year for Cristobal,' Harry said.

'Quite a year for Spain!'

The door to Colon's ocean adventure had finally opened in November of last year, when Boabdil, the last emir of al-Andalus, signed a treaty of surrender. On 6 January 1492, the monarchs themselves entered Granada. They were dressed respectfully in the Moorish style, Isabel radiant in a turban and an embroidered caftan, but the sweet voices of the royal choir sang hymns to Christ, which echoed through the empty stone streets. It was a tremendous victory for Christendom, the conclusion of eight centuries of dedicated reconquest, and the news of it rang out across Europe.

And in April Colon was summoned to the monarchs' court once more. The monarchs received him in the Alhambra itself, in a chamber the Moors had called the Hall of the Mexuar, a room in the oldest part of the palace where the daylight was filtered through the stained glass of a lantern roof. In this architectural triumph of a vanquished people, amid rooms inscribed with Moorish slogans – Wa la ghalib illa Allah, there is no conqueror but Allah – Colon's contract documents were sealed. He was given a letter from Fernando and Isabel to the Great Khan of the Mongols. And as a final flourish Colon begged the monarchs to devote all the treasure raised by his expedition to the reconquest of Jerusalem.

But Colon would not be able to sail from Seville or Malaga, for those great ports were choked with fleeing Jews.

He headed for little Palos on the Tinto estuary instead; Colon was glad to honour the town where he had found such support from the brothers of La Rabida. But on the road Colon was caught up in great chains of refugees, more Jews, struggling to get to the coast. Some of them carried shards of the shattered tombstones of their ancestors. They were dusty, exhausted, ill; some helpless mothers even gave birth on the road. But their rabbis made the women sing and play tambourines to raise the people's spirits. And even when Colon reached Palos he had trouble securing ships, for all the masters were busy with the urgent task of transporting Jews.

Just at this moment when it was preparing to reach out across the world, Spain was cleansing itself.

Geoffrey said, 'What a terrible mistake the expulsion could prove to be! Torquemada's bitter heart may be brimming. But Spain is stripping herself of her most industrious citizens – of a whole class of bankers and moneylenders, artists and administrators; no hidalgo or caballero would lower himself to such work. Just as she is on the verge of empire, Spain is ridding herself of the talents she needs to run it. Ha!

'And the Moors will surely follow the Jews out of Spain sooner or later, whatever promises the monarchs have made. What will become of the Moors I don't know, for though their ancestors came from the deserts of Africa and Araby, they don't belong there now any more than you or I would have a place in the German forests of our own forebears. Perhaps they will simply dissipate, a vanished people, leaving behind their palaces and books, and the future will wonder that a Muslim nation once flourished in western Europe…'