No wonder she felt angry.

But before all that how wonderful life had been in Grandmamma’s house in Hesse Darmstadt, where Grandmamma was the Landgravine. They had gone there because their stepmother had died giving birth to little Charles. Their mother had died two years before, also in childbed, and the child had died with her.

Charlotte, their eldest sister, had married the Duke of Hildburghausen, so she did not accompany the younger ones to Grandmamma Landgravine. There were just Thérèse, Louise, Frederica, George – who was a year younger than Frederica – and now stepbrother baby Charles.

They were happy carefree days which had perhaps helped to make her what she was. The Landgravine was a clever woman. She wanted the children to be happy so she gave them a certain amount of freedom, but at the same time she introduced them to music and the arts and saw that they were endowed with all the social graces. Recognizing the outstanding beauty of the girls, she decided that as they grew older no opportunities should be missed. Thérèse immediately found a princely husband, and the Landgravine then turned her attention to Louise and Frederica.

Life went on gaily, full of trivial excitements, until the carefree existence was brought to a sudden halt. Revolution had crippled France and from the ruins had risen the Corsican adventurer whose dream was to dominate Europe. The Landgravine was alert as each day came news of Napoleon’s successes and every hour brought his invading armies to their home.

It was unsafe, the Landgravine decided; and the girls were sent off to their sister Charlotte.

They were young and lively and the war seemed far away from lovely Hildburghausen in the sweet-smelling pine forest. Charlotte gave balls and banquets to launch her sisters whose beauty had become a legend; Louise and Frederica were the two loveliest girls in Germany, it was said; and they were clearly looking for husbands.

How happy they had been – she and Louise! Everywhere they went they were together. They spoke of each other as one person. ‘Louise and I do this.’ ‘Frederica and I think that.’ They had never thought in those days that separation must inevitably come. Their brother George, who was as gay and vivacious as his sisters, was their staunch ally; he adored them and they him; but in the case of Louise and Frederica they were as one.

Snatches of conversation came back to Frederica now as she lay in bed in Berlin. ‘But, dearest Freddi, when we marry we shall have to part.’ ‘Then I won’t marry. I’ll stay with you! I’ll be your companion. Your dresser. Your lady-in-waiting. I’d rather be with you than marry a King.’ ‘Always so wild,’ chided Louise. ‘If they decided you’d marry, you’d have to. But when I marry I shall invite you to stay with me and you must invite me to stay with you.’ ‘I don’t want to be a guest in your house, Louise. I want to belong.’

And then came that night in Frankfurt through which they had passed on their way home with the Landgravine who had come to collect them from Hildburghausen; there was great excitement because the King of Prussia with his two sons was in the town and it would be unthinkable for two such highly-born ladies not to pay their respects to the monarch. Besides, with him were his two unmarried sons.

The inevitable happened. Or had it been planned? The sons of the King of Prussia needed brides; and the Princesses of Mecklenburg-Strelitz needed husbands.

After that first meeting, the King told the Landgravine that her granddaughters were as beautiful as angels, and that his sons had fallen in love with them at first sight.

Although, thought Frederica ironically, it was not clear with whom the Crown Prince had fallen in love – herself or Louise. As for his brother Prince Louis, he was immersed in his own private love affair, and was unimpressed by either of the beautiful girls who were paraded for his approval.

He had told her afterwards, when they were married, that he knew he had to take one of them and it hadn’t mattered to him a jot which, and the Crown Prince felt the same but as he had to make a choice he took Louise, who talked less and apart from the fact that her neck was too short which gave her a humped look, was quite beautiful.

But then Louis had disliked her because she had been a necessity. But not more than she disliked him, of course. And if Louise’s neck was a little short it was her only imperfection and was easy to disguise by the lovely gauzy draperies she affected.

But the sisters were ecstatically happy because if they married the brothers they would live at the same Court and their fears of separation were groundless. For the rest of their lives they would continue to say: ‘Louise and I think this.’ ‘Frederica and I do that.’

Who cared for husbands? Louise did a little. But that was Louise, gentle, sentimental, and when she started bearing his children she felt a strong affection for the Crown Prince and he for her. Frederica was different. She was more proud, more eager to go her own way and not so docile as Louise. Louis had done his duty by marrying her; he had got her with child; his duty was completed until the time came to produce another child so he could return to his mistress.

Let him. What did she care? She could dance, amuse herself, surround herself with admirers.

I am, she thought, picking up a mirror from the table beside her bed, the kind of woman about whom there will always be scandal – even now.

What had she cared? She had danced through the night, made assignations with men; lived wildly and feverishly, but the happiest times were when she was alone with Louise, while Louise was waiting for a child to be born; then they were at peace, listening to music or making it themselves, talking of the children, laughing over the old days.

She had her beautiful baby, Frederick William Louis, and she loved him; but she had never been a domesticated woman. It might be different now, she believed. She was mature where she had been young, serious where she had been lighthearted; she loved one man, whereas in those butterfly days she had been humiliated by her husband’s indifference and perhaps determined to prove that he was the only man who did not find her attractive.

While awaiting the birth of her daughter, Frederica Wilhelmina Louise, she and Louise had lived their quiet completely satisfying life together; but the time came when she was rejoined by her husband, and soon after that he died. It was said to be a fever, but the whisperings had begun then. Everyone knew that she disliked him; they were unfaithful to each other; and he was so young to die. What was this fever? What had caused it? No one could be sure.

She was a widow of nineteen with two babies and her reputation for frivolity had changed a little. There was a sinister tinge to it.

She laughed thinking of it. What had she cared. She would rather be thought a wicked woman than a fool. Louis had treated her shamefully – and Louis had died. Perhaps that would be remembered if anyone else decided to treat her badly.

It was not to be expected that she would remain unmarried; and if a husband was found for her she might have to leave the Court of Berlin.

‘I won’t do that,’ she had declared.

But she knew they would force her to it.

Her family was very proud of its connections with the Court of England, which was natural when one compared little Mecklenburg-Strelitz with that great country. All her life she had heard references to ‘your Aunt, Queen Charlotte of England’. It was a legend in the family – the story of how one day news had come to her grandfather that his daughter the Princess Charlotte was sought in marriage by King George III.

And that same Charlotte had many sons and one of these, Adolphus, the Duke of Cambridge, was four years older than Frederica, entirely eligible, and of course the English royal family could have no objection to his marriage with a niece of the Queen.

Adolphus came to Berlin. No one could dislike Adolphus; he was too mild and pleasant. Dull, was Frederica’s comment. And if I married him I should have to leave Louise.

She talked the matter over with Louise. ‘We’d be parted,’ admitted Louise, ‘and that would make us most unhappy. But you have to marry, Freddi, and Adolphus is very kind.’

‘I wonder what it’s like at the English Court with that old legend Aunt Charlotte in command.’

‘There is a king, you know. And the Prince of Wales is said to be the most exciting Prince in Europe.’

‘Ah, the Prince of Wales! Why didn’t they offer me him instead of Adolphus?’

‘Adolphus will be good to you.’

‘And what of us?’

‘You must ask him to bring you here often. Perhaps you could settle here. Why not? He could live in Hanover. They might give him a position there.’

‘That’s true. I see I could do worse than Adolphus.’

And so she had become betrothed to him, and was becoming moderately reconciled to marriage when she met Frederick William, Prince of Solms-Braunfels, a Captain of the King’s Bodyguard, who had seemed at that time devastatingly attractive. Was it because he was so different from Adolphus – gay and dashing and determined to seduce her?

‘But I am betrothed to the Duke of Cambridge,’ she protested.

‘Do you think I should allow that young man to stand in my way?’ demanded Frederick William of Solms-Braunfels.

Frederick William certainly had a way with him, and perhaps she was in rebellion against those who would choose her husband for her, and against the legend of Aunt Charlotte.

It was not enough to make her his mistress. That was a secret affair. He wanted to flout the Duke of Cambridge, to throw his defiance at the English Duke; he wanted the world to know that the beautiful Frederica was so enamoured of her bold captain that she would turn from mighty England to little Solms-Braunfels. And she had believed it was due to his passion for her! She married him secretly, and made one of the biggest mistakes of her life.