Unlike Charles' previous mistress Barbara Palmer, who had openly insulted the Queen, de Kéroualle was careful to show her every respect, and relations between the two women were never less than amicable.

Yet when there appeared a prospect that Charles would show her favour, the intrigue was vigorously pushed by the French ambassador, Colbert de Croissy, who was aided by the English secretary of state Henry Bennet, 1st Earl of Arlington, and his wife.

De Kéroualle, who concealed cunning and ambition under an appearance of languor and a rather childlike beauty (diarist John Evelyn speaks of her "baby face"), yielded to Charles' romantic advances only after she had established a strong hold on his affections.

[10] Louis XIV gave her a pair of earrings worth the astonishing sum of eighteen thousand pounds, his most expensive gift to England that year and more lavish than anything he had ever given Charles' queen.

[11] Louise is mentioned in "A Satyr on Charles II", a 1673 poetical lampoon at the King's expense, written by John Wilmot, Earl of Rochester, in which she is referred to with her last name spelt Carwell.

At that time Charles II himself happened to request a specific piece by Rochester—who, upon delivery, discerned that he had delivered directly into the hands of the King the impudent satire aimed at his person instead of the sought-after text.

She contrived to escape uninjured during the crisis of the "Popish Plot" in 1678, and found an unexpected ally in Queen Catherine, who was grateful for the kindness and consideration Portsmouth had always shown her.

That Charles was truly attached to her is shown by his dying instruction to his brother to "do well by Portsmouth",[14][notes 1] making her one of three women in his life, along with the Queen and Nell Gwynne, who were in his thoughts at the end.

[15] During her last years, Portsmouth lived at Aubigny under mounting debt, but she received a pension and protection against her creditors from king Louis XIV and later the regent Philippe II.