Until that time in my life, I do not believe I ever enjoyed the company of a female companion so similar in age and disposition to me. I had borne a natural affection for my sister, Lady Catherine, and a deep and enduring admiration for Mrs Mahon, but neither shared my interests or temperament. Even Mrs Elliot felt more to me a mother than a friend. Unlike these ladies, Agnès de Buffon’s mind whirred like a waterwheel. She contemplated and cogitated; she devoured works of philosophy and debated their merits. Although an incorrigible coquette, she did not clutter her head with tales of gossip and scandal. It was she who first placed into my hand Madame de Gouges’s Declaration of the Rights of Woman as well as that work upon a similar subject by Mrs Wollstonecraft.

‘I do not agree with all she advocates. Indeed, I think Mrs Wollstonecraft most priggish at times,’ she remarked. ‘I should never wish Orléans to think I subscribed to such notions. Madame de Genlis counselled me to maintain my silence, to master the appearance of stupidity and charm, or else I should become suspect in the eyes of all Orléans’s associates. The more clever appears the mistress, the more foolish appears the lover, she cautioned me.’ La Buffon laughed. ‘It was that very quality – cleverness – which undid Madame de Genlis. She did not wish me to suffer as she had.’

We continued to stroll through the cool, shadowed wood that bordered La Volière, listening to the wind shaking the many millions of leaves.

‘I shall tell you a secret,’ La Buffon began with a mischievous look. ‘I have begun to write a novel. It is an allegory of a noblewoman who travels to a foreign land where her title is of no consequence and where the sexes are born equal. I write in private, in the mornings. I have told no one of this but you. Promise me that you will not speak of it to Orléans . . . or anyone.’

Of course I promised, and of course that promise was broken almost as instantly. I said nothing to the Duke, but rather disclosed the details to Mrs Elliot, though not without some sharp pricks of conscience.

My entire sojourn at La Volière seemed to follow in that vein: a sequence of unexpected pleasures tinged with private disquiet. Dishonesty and trust walked hand in hand unbeknownst to one another. Although I greatly enjoyed Madame’s society, some part of me prayed that my time there would soon be brought to a conclusion.

If I have learned anything in the course of my varied life, it is that one must take great care with prayers. They are often answered, but in a manner most unanticipated.

That for which I had hoped came, quite without warning, on a night in early August. A rider arrived from the camp at Valenciennes with an urgent message for La Buffon.