And when she stood before him and lifted her eyes to his eager ones, she saw a man in his forties; and that seemed to her very old. She was trembling, but she smiled and greeted him as though with pleasure. All the time she was aware of those two men who had determined to set her on the throne – the Duke of Arevalo and the Marquis of Villena.

Alfonso took her hand and led her to two ornate chairs which had been set side by side. As they took their seats he said: ‘My dear Princess, you must not be afraid of me.’

‘I am so young for marriage,’ Joanna answered.

‘Youth is a blessing, compared with which the experience which comes with age is but a small compensation. Do not deplore your youth, my dear one, for I do not.’

‘Thank you, Highness,’ she whispered.

‘You look uneasy. Do you so fear me?’

‘We are very closely related. You are my mother’s brother.’

‘Have no fear, my dear. A messenger is being dispatched to the Pope. He will send us a dispensation without delay.’

She could not endure his inquiring tender gaze, and she feigned relief.

Alfonso felt happy. He was a man who must for ever pursue some cause, and he preferred it to be a romantic one. He had had great success against the Moors, but fighting the Moors was a commonplace occupation in the Iberian Peninsula. Now here was a young girl – his own niece – in need of a champion. To some she was the rightful heiress to the throne; to others the late Queen’s bastard. Her cause appealed to him because she was young and he, a widower, could make her his bride. This was the most romantic cause in which he had ever fought, and it delighted him – particularly as victory could bring such benefit to him.

He was not a man to bear a grudge, but he could not forget his meeting with the proud Isabella, who had shown so openly her distaste for marriage with him – King though he was.

It was not unpleasant therefore to contemplate the discomfiture of the haughty Isabella when she found herself ousted from the throne by the man whom once she had so recklessly refused.

He was smiling as he took Joanna’s hand, and those assembled, led by Villena and Arevalo, proceeded to declare Alfonso and Joanna Sovereigns of Castile.

As soon as the dispensation from the Pope arrived they would be married. Joanna prayed that the dispensation might be delayed.

In the meantime, the betrothal was celebrated, and on this and all occasions she must sit side by side with Alfonso and accept his tender attentions.

After some days Alfonso and his army, Joanna travelling with them, left Placencia for Arevalo.

Being aware of the sad state of the Castilian armies and that Isabella and Ferdinand had inherited a bankrupt state, Alfonso anticipated a victory which would be easy to complete.

At Arevalo he paused in his journey, and it seemed as though he halted there to prepare himself for the attack.

Isabella and Ferdinand were together when news was brought to them of Alfonso’s arrival at Placencia and of his betrothal to Joanna.

Ferdinand received the news gloomily. ‘This means he is prepared to risk his armies in her cause,’ he said.

‘She is his niece,’ cried Isabella, ‘and but a child.’

‘What cares he for either fact! He thinks she will bring him Castile and, if he is successful, depend upon it the Pope will not long deny him the dispensation he needs.’

‘If he is successful. He shall not be successful! I promise you that.’

‘Isabella, what do you know of war? And how can we prevent him?’

‘I know,’ she said, her eyes flashing, ‘that I was born to be Queen of Castile.’

‘Well, you have had your brief glory.’

‘I have done nothing of what I intend to do. I know I shall succeed.’

Ferdinand took her gently by the arm and led her to a table on which a map was spread.

He pointed to South Castile. ‘Here,’ he said, ‘the friends of Alfonso are waiting. They are numerous and they have men and arms at their disposal. Arevalo, Villena, Cadiz . . . they are his men. They will give all they have to drive us from the throne and set up Joanna and Alfonso. He has only to turn south tomorrow and there traitors will be ready for him. Town after town will freely give itself into his hands. And we . . . we shall find ourselves unable to attack, for on his march through Castile he will grow richer and richer as important towns pass into his possession.’

Ferdinand,’ Isabella reproved him, ‘I do not understand you. Have we not our friends?’

‘There are waverers.’

‘Then they shall cease to be waverers.’

‘They will cease to be when they see the might of Alfonso’s army!’

‘They must be converted to our cause.’

‘But who shall convert them?’

‘I shall. I . . . their Queen.’

Ferdinand looked at her with mild surprise; there were times when he felt that even now he did not know Isabella. She seemed so dedicated to her cause, so certain of her ability to fight and win in this unequal struggle, that Ferdinand believed her.

It was at times like this that he forgave her for insisting on her supremacy, when he was glad that he had not returned to Aragon in a fit of pique because she had been determined to be supreme in Castile.

‘You forget, Isabella,’ he said gently, ‘you are in no fit state to conduct a campaign. You have our unborn son to think of.’

‘It is because of our unborn son that I must be doubly sure that none shall rob me of the throne,’ she told him.

Isabella had lived through many hazards, but she felt that never had she faced danger so great as that which threatened during the months that followed. The days were full and she worked far into the night. She spent a great deal of time at prayer, for she was sure that she had previously been granted Divine protection and that it would be afforded her again.

Yet, even while she prayed, she never forgot that if she were to win heavenly aid she must neglect nothing of which her human strength was capable.

She would sit during the night receiving from and sending messages to the pitiably few troops she possessed. That was not all. She had decided that she herself must visit those towns which, she feared, were waiting to see which was the stronger party before bestowing their allegiance.

She set out on a tour of these towns. Riding was difficult; the roads were rough and the hours she was forced to spend in the saddle were very irksome, as with each passing week her pregnancy became more apparent.

It was impossible for the townsfolk to see Isabella and listen to her without being deeply affected. Isabella was inspired; she believed in her destiny; she knew she could not fail, and she conveyed this certainty to many of those whom she had come to rally to her standard.

Ferdinand was with her army endeavouring to prepare it for the attack, which, for some strange reason, Alfonso was hesitating to make. Each day both Ferdinand and Isabella expected to hear that Alfonso was on the march; they dreaded to hear that news.

‘Give us a few more weeks,’ prayed Isabella. ‘Then we shall not be so vulnerable.’

‘A month . . . two months of preparation,’ declared Ferdinand to his generals, ‘and, if the Queen continues to rally men to our cause as she has begun to do, I think we shall give a very good account of ourselves and soon send Alfonso marching back across the frontier. But we need those weeks . . . we need them desperately.’

So while they worked they watched anxiously for Alfonso to move; yet he remained at Arevalo awaiting, he said, the arrival of his Castilian supporters, so that when he attacked there should be one decisive battle.