‘Oh, Isabella, my wife, my Queen,’ he murmured to himself, ‘you will have to learn something of the world one day. You will have to know that men, such as I am, who spend long periods away from the conjugal bed, cannot be denied a mistress now and then.’

And from love affairs such as that which he had enjoyed with the Viscountess of Eboli there were often results.

Ferdinand smiled. He was confident of his powers to obtain what he would from all women – even his sedate, and rather alarmingly prim, Isabella.

He was remembering the occasion when he and the Viscountess had become lovers. It was during one of those spells when he was away from Castile, in Catalonia on his father’s business. It was Isabella who had insisted that he leave her. ‘It is your duty to go to your father’s aid,’ she had said.

Duty! he thought. It was a word frequently recurrent in Isabella’s vocabulary.

She would never fail to do her duty. She had been brought up to regard it as of paramount importance. She would risk her life for the sake of duty; she did not know, she must not guess that, when she had allowed her husband to depart into Catalonia, she had risked his fidelity to their marriage bed.

It had happened. And now here he was at the Eboli mansion; the house was stirring and the cry went forth: ‘He is come! The Master is within the gates.’

When he had given his horse to the waiting groom, he said: ‘Softly, I pray you all. This is an unofficial visit. I am passing on my way to Aragon and I but pause to pay a friendly call.’

The servants understood. They knew of the relationship between their mistress and Don Ferdinand. They did not speak of it outside the household. They knew that it was the wish of Don Ferdinand that this should be kept secret, and that it could be dangerous to offend him.

He had stepped into the house.

‘Your mistress?’ he asked of two women who had immediately dropped deep curtsies.

‘She had retired for the night, Highness. But already she has heard of your coming.’

Ferdinand looked up and saw his mistress at the head of the staircase. Her long dark hair fell in disorder about her shoulders; she was wearing a velvet robe of a rich ruby colour draped round her naked body.

She was beautiful; and she was faithful. He saw the joy in her face and his senses leaped with delight as he bounded up the stairs and they embraced.

‘So . . . you have come at last . . .’

‘You know that I would have been here before this, could I have arranged it.’

She laughed, and keeping her arms about his neck, she said: ‘You have changed. You have grown older.’

‘A fate,’ he reminded her, ‘which befalls us all.’

‘But you have done it so becomingly,’ she told him.

They realised that they were being watched, and she took his arm and led him into her bedchamber.

There was a question which he wanted to ask above all others. Shrewdly he did not ask it . . . not yet. Much as she doted on the child, she must not suspect that it was for his sake that he had come and not for hers.

In her bedchamber he parted the velvet gown and kissed her body. She stood as though her ecstasy transfixed her.

He inevitably compared her with Isabella. Any woman, he told himself, would seem like a courtesan compared with Isabella. Virtue emanated from his wife. It surprised him that a halo was not visible about her head. Everything she did was done as a dedicated act. Even the sexual act – and there was no doubt that she loved him passionately – appeared, even in its most ecstatic moments, to be performed for the purpose of begetting heirs for the crown.

Ferdinand made excuses to himself for his infidelity. No man could subsist on a diet of unadulterated Isabella. There must be others.

Yet now, as he made love to his mistress, his thoughts were wandering. He would ask the all-important question at precisely the right moment. He prided himself on his calmness. It had been the admiration of his father and mother. But they had admired everything about him – good and bad qualities. And there had been times when he had been unable to curb his impetuosity. They would become fewer as he grew older. He was fully aware of that.

Now, satiated, his mistress lay beside him. There was a well-satisfied smile on her lips as he laced his fingers in hers.

‘You are superb!’ whispered Ferdinand. And then, as though it were an afterthought: ‘And . . . how is the boy?’

‘He is well, Ferdinand.’

‘Tell me, does he ever speak of me?’

‘Every day he says to me: “Mother, do you think that this day my father will come?”’

‘And what do you say to that?’

‘I tell him that his father is the most important man in Aragon, in Catalonia, in Castile, and it is only because he is such an important man that he has not time to visit us.’

‘And his reply?’

‘He says that one day he will be an important man like his father.’

Ferdinand laughed with pleasure. ‘He is sleeping now?’ he said wistfully.

‘Worn out by the day’s exertions. He is a General now, Ferdinand. He has his armies. You should hear him shouting orders.’

‘I would I could do so,’ said Ferdinand. ‘I wonder . . .’

‘You wish to see him. You cannot wait. I know it. Perhaps if we were very quiet we should not wake him. He is in the next room. I keep him near me. I am always afraid that something may happen to him if I let him stray too far from me.’

‘What could happen to him?’ demanded Ferdinand suddenly fierce.

‘Oh, it is nothing, merely the anxieties of a mother.’ She had risen and put her robe about her. ‘Come, we will take a peep at him while he sleeps.’

She picked up a candlestick and beckoned to Ferdinand, who threw on a few clothes and followed her to a door which she opened quietly.

In a small cot a boy of about three years was sleeping. One plump hand gripped the bedclothes, and the hair which curled about the well-shaped head had a gleam of chestnut in its brown.

This was a very beautiful little boy, and Ferdinand felt an immense pride as he looked down on him.

He and Isabella had a daughter, but this was his son, his first-born son; and the chubby charm and the resemblance to himself filled Ferdinand with an emotion which was rare to him.

‘How soundly he sleeps!’ he whispered; and he could not resist stooping over the bed and placing his lips against that soft head.

In that moment an impulse came to him to pick up the sleeping child and to take him from his mother, to take him into Castile, to present him to Isabella and say to her: ‘This is my son, my first-born son. The sight of him fills me with joy, and I will have him brought up here at Court with any children you and I may have.’

He could never do such a thing. He imagined Isabella’s reactions; and one thing he had learned since his marriage was the necessity of respecting Isabella in all her queenly dignity.

What a foolish thought when what he had to do was prevent Isabella’s ever hearing of this child’s existence.

The little boy awakened suddenly. He stared up at the man and woman by his bedside. Then he knew who the man was. He leaped up and a pair of small hot arms were about Ferdinand’s neck.

‘And what is the meaning of this?’ cried Ferdinand in mock anger.

‘It means my father is come,’ said the child.

‘Then who are you?’ asked Ferdinand.

‘I am Alonso of Aragon,’ was the answer, and spoken like a Prince. ‘And you are Ferdinand of Aragon.’ The boy put his face close to Ferdinand’s and peered into it; with his forefinger he traced the line of Ferdinand’s nose.

‘I will tell you something,’ he said.

‘Well, what will you tell me?’

‘We are something else too.’

‘What is that?’

‘You are my father. I am your boy.’

Ferdinand crushed the child in his arms. ‘It is true,’ he said. ‘It is true.’

‘You are holding me too tightly.’

‘It is unforgivable,’ answered Ferdinand.

‘I will show you how I am a soldier now,’ the boy told him.

‘But it is night and you should be asleep.’

‘Not when my father has come.’

‘There is the morning.’

The boy looked shrewd and at that moment was poignantly like Ferdinand. ‘Then he may be gone,’ he said.

Ferdinand’s hand stroked the glossy hair.

‘It is his sorrow that he is not with you often. But tonight I am here and we shall be together.’

The boy’s eyes were round with wonder. ‘All through the night,’ he said.

‘Yes, and tomorrow you will sleep.’

‘Tomorrow I will sleep.’

The boy leaped out of bed. He was pulling open a trunk. He wanted to show his toys to his father. And Ferdinand knelt by the trunk and listened to the boy’s chatter while his mother looked on and ambition gleamed in her eyes.

After a while the boy said: ‘Now tell me a story, Father. Tell me of when you were a soldier. Tell me about battles . . . and fighting and killing.’

Ferdinand laughed. He sat down and nursed the boy in his arms.

And Ferdinand began to tell a story of his adventures, but before he was halfway through his son was asleep.

Ferdinand laid him gently in his bed, then with the boy’s mother he tiptoed out of the room.

She said with a sudden fierceness: ‘You may have legitimate sons, princes born to be kings, but you will never have a child whom you can love as you love that one.’

‘I fear you may be right,’ said Ferdinand.

The door between the two rooms was fast shut, and Ferdinand leaned against it, looking at his mistress in the candlelight; she was no less beautiful when her eyes shone with ambition for her son.