He would take the boy on his knee and tell him of the journeys he had made. He would talk of voyages to the coast of Guinea and Iceland, to the Cape de Verd Islands. He talked of the time when he had first come to Lisbon. Filippa had come with him; and she had known what he planned; he had made no secret of his ambitions. She had understood. She was her father’s daughter and he had sailed the seas; he understood the desire of men to discover new lands. So Filippa Muñiiz de Palestrello understood also.

She had watched her husband and her father bending over the charts, growing excited, talking of what lay beyond the wastes of water so far unexplored by Europeans.

When her father died all his charts and all his instruments were left to Christoforo, who had by then married Filippa.

One day Christoforo, who had vainly been trying to interest influential men in his projects, heard that an adventurer was more likely to get a sympathetic understanding in the maritime port of Lisbon than anywhere else, for King John II of Portugal was interested in expeditions into the unknown world.

‘Pack up what we have, Filippa,’ he had said. ‘This day we leave for Lisbon.’

And so to Lisbon they had come, and found a home here among its seven hills. But Filippa had died, leaving him only Diego to remind him of her – Diego, that precious and beloved creature, who because of the dream must be an anxiety.

Wandering along the banks of the Tagus, walking disconsolately through the Alfama district, gazing up to the Castle of Sao Jorge set on the highest of the hills, he dreamed continually of the day when he would leave Lisbon; for his dream had become an obsession which tormented him, and had grown to such proportions that it obliterated even the love of his wife and child.

‘But one day, Diego, my son,’ said Christoforo, ‘they will not laugh. One day they will honour your father. Mayhap they will make him an Admiral and I shall ask a place at Court for you, my little son.’

Diego nodded; he had no idea what a place at Court would mean to him, but he was pleased that his father did not forget him; for young as he was, Diego understood the force of his father’s ambition.

‘Father,’ he said, ‘will it be soon that you sail away?’

‘Soon, my son. It must be soon. I have waited long. And while I am away, you will be good?’

‘I will be good,’ said the boy, ‘but I shall long for your return.’

Christoforo was smitten with remorse afresh. He lifted the boy in his arms and held him tightly. Little Diego had such confidence in his father who was preparing to leave him, and indeed longing to do so. He did not doubt that provision would be made for him during his father’s absence, and in the event of his father’s not returning at all.

And it shall be! Christoforo assured himself. Even if I have to take him with me.

Yet what sort of a father-was he, to expose a tender child to the hazards of the sea!

I am not a father, Christoforo told himself, any more than I was a husband. I am an explorer-adventurer – and there is little space in one lifetime to be more than that. Yet, I swear, Diego shall be cared for.

He set the boy on his knee and took out one of the charts which had been left to him by his father-in-law. He showed the boy where he believed the new land to lie, and as he talked he was railing against this fate which prevented him from making the voyage of his dreams. If he were but a rich man . . . But he was a poor adventurer who had to depend on the wealth of others to finance his venture; and in some ways he was a practical man; he knew that great wealth would have to be expended on an expedition such as he wished to lead. Only great nobles could help; only kings.

But nothing could be done without the approval of the Church; and the Church was inclined to laugh at his proposals.

The Bishops wanted verification of his assumptions. What were the chances of success? Could they put their trust in the dream of an adventurer? They did not believe in the existence of this great undiscovered land.

Yet they had allowed him to hope.

It was while he sat with his son that a visitor called to see him. Christoforo’s heart leaped as the man entered the shop. He knew that he had not come to buy nautical instruments, for he was in the service of the Bishop of Ceuta.

Christoforo rose hastily and pushed Diego from his knee.

‘Leave us, my son,’ he said.

And Diego ran up the spiral staircase, but he did not enter the room above the shop; he sat on the top stair listening to the voices below. He could not hear what was said but he would know by the sound of his father’s voice whether the news was good. Good news would be that his father might prepare immediately to make the voyage, and although Diego knew that would mean separation, no less than his father he longed to hear this news. For Diego, like Christoforo, there could only be real satisfaction when the dream became reality; and like his father, the boy was ready to endure any hardship if this should come to pass.

Meanwhile Christoforo had taken his visitor into the dark little room beyond the shop.

Christoforo’s heart had sunk at the sight of the man’s face; he had seen that expression on faces before, the faintly suppressed smile of superiority which men of small understanding, who thought themselves wise, gave to those who in their opinion bordered on imbecility.

‘I come from my lord Bishop of Ceuta,’ said the man.

‘And your news?’

The man shook his head. ‘Nothing more can be done. The voyage is impossible.’

‘Impossible!’ cried Christoforo rising, his blue eyes blazing. ‘How can any say this of that which has not been proved?’

‘It had been proved.’ The man’s smile widened. ‘The Ecclesiastical Council decided that your project would be a hopeless one, but his lordship, the Bishop of Ceuta, did not dismiss your claims as lightly as did the others.’

‘I know,’ said Christoforo, ‘he promised me that ere long I should be equipped with all I needed to make the voyage.’

‘Meanwhile his lordship decided to put your theories to the test.’

‘But he has not done so. I have been here in Lisbon these many months . . . waiting . . . waiting, eternally waiting.’

‘But he has done this. He sent his own expedition. He equipped a vessel and sent her out in search of this new world which you are so sure exists.’

Christoforo was fighting hard to restrain himself. He was not a meek man, and he wanted to crash his fist into the smiling face. They had cheated him. They had listened to his plans; they had studied his charts. It had been necessary to convince them that he had something to support his theories. Then they had deceived him. They had equipped a vessel for someone else.

‘The ship returned, battered and almost unseaworthy. It is a miracle that she arrived back safely in Lisbon. She encountered such storms in the Saragossa Sea that it was impossible to continue the journey. In fact, the discovery has been made that the journey is impossible.’

Christoforo’s rage was tempered with relief. The failure of others did not affect his dream.

He held it intact, but he had made one important discovery. He could expect no help in Lisbon. He had wasted his time.

‘You are now convinced that what you propose is impossible, I hope?’ he was asked.

Christoforo’s eyes were as hard and brilliant as aquamarines.

‘I am convinced of the impossibility of getting help from Portugal,’ he said.

Now the visitor was smiling broadly. ‘I trust business is good?’

Christoforo lifted his hands in a gesture of despair. ‘What do you think, my good sir? Do you think that Lisbon is a city of adventurers who would be interested in my charts and instruments?’

‘Sailors need them on their journeys, do they not?’

‘But in Lisbon!’ said Christoforo, his anger rising. ‘Perhaps the sale of such articles would be more profitable in towns where men do not set out to sea and then allow a storm or two to drive them back to port.’