The young duchess, though an English princess, had at heart the interests of the country in which she had been reared, and which on her marriage she had adopted as her own. She therefore gladly undertook this mission, confident of her success from the fact that of all his family she had ever been the most tenderly beloved by Charles. Therefore she set out from France, and in the month of May, 1670, arrived at Dover, to which port the king, Queen, and court hastened, that they might greet and entertain her. For full ten days in this merry month, high revelry was held at Dover, during which time Henrietta skilfully and secretly effected the object of her visit. And her delight was now the greater, inasmuch as one item which this agreement entrusted her to make, engaged that Charles would, as soon as he could with safety, follow the example of his brother the Duke of York, and become a Catholic. In carrying out this purpose Louis promised him substantial aid and sure protection. Likewise, it may be mentioned, did the French king engrage to grant him a subsidy equal to a million a year, if Charles joined him in an attack on Holland.

The prospect of his sister's return filled the king with sorrow, which increased as the term of her visit drew to an end. "He wept when he parted with her," wrote Monsieur Colbert, the French ambassador, who significantly adds, "whatever favour she asked of him was granted."

Now Louis knowing the weakness of the English monarch's character, and aware of his susceptibility to female loveliness, had despatched Mademoiselle de Querouaille in the train of Henrietta. Satisfied that Charles could not resist her charms, the French monarch had instructed this accomplished woman, who was trusted in his councils, to accept the royal love, which it was surmised would be proffered her; so that by the influence which she would consequently obtain, she might hold him to the promises he might make the Duchess of Orleans.

As had been anticipated, the king became enamoured of this charming woman, who, before departing with the princess, faithfully promised to return and become his mistress. In his desire to possess her the merry monarch was upheld by his grace of Buckingham, who, continuing in enmity with the Duchess of Cleveland, resolved to prevent her regaining influence over the king by adding the beautiful Frenchwoman to the number of his mistresses. He therefore told Charles, in the sarcastic manner it was occasionally his wont to use, "it was a decent piece of tenderness for his sister to take care of some of her servants;" whilst on being sent into France, he assured Louis "he could never reckon himself sure of the king, but by giving him a mistress that should be true to his interests." But neither king required urging to a resolution on which both had separately determined; and soon Mademoiselle Querouaille was ready for her journey to England. A yacht was therefore sent to Dieppe to convey her, and presently she was received at Whitehall by the lord treasurer, and her arrival celebrated in verse by Dryden. Moreover, that she might have apartments in the palace, the king at once appointed her a maid of honour to her majesty, this being the first of a series of favours she was subsequently to receive. Evelyn, writing in the following October, says it was universally reported a ceremonious espousal, devoid of the religious rite, had taken place between his majesty and Mademoiselle Querouaille at Lord Arlington's house at Euston. "I acknowledge," says this trustworthy chronicler "she was for the most part in her undresse all day, and that there was fondnesse and toying with that young wanton; nay, 'twas said I was at the former ceremony, but 'tis utterly false; I neither saw nor heard of any such thing whilst I was there, tho' I had ben in her chamber, and all over that apartment late enough, and was myself observing all passages with much curiosity."

She now became a central figure in the brilliant court of the merry monarch, being loved by the king, flattered by the wits, and tolerated by the queen, to whom—unlike the Duchess of Cleveland—she generally paid the greatest respect. Her card tables were thronged by courtiers eager to squander large sums for the honour of playing with the reigning sultana; her suppers were attended by wits and gallants as merry and amorous as those who had once crowded round my Lady Castlemaine in the zenith of her power. No expense was too great for his majesty to lavish upon her; no honour too high with which to reward her affection. The authority just mentioned says her apartments at Whitehall were luxuriously furnished "with ten times the richnesse and glory beyond the Queene's; such massy pieces of plate, whole tables and stands of incredible value." After a residence of little more than three years at court she was raised by King Charles to the peerage as Baroness of Petersfield, Countess of Farnham, and Duchess of Portsmouth; whilst the French king, as a mark of appreciation for the services she rendered France, conferred upon her the Duchy of Aubigny, in the province of Berri in France, to which he added the title and dignity of Duchess and Peeress of France, with the revenues of the territory of Aubigny. And two years later King Charles, prodigal of the honours he conferred upon her, ennobled the son she had borne him in 1672. The titles of the Duke of Richmond and Lennox having lately reverted to the crown by the death of Frances Stuart's husband, who was last of his line, the bastard son of the French mistress was created Duke of Richmond and Earl of March in England, and Duke of Lennox and Earl of Darnley in Scotland. To these proud titles the present head of the noble house of Richmond and Lennox—by virtue of the grant made by Louis XIV. to his ancestress likewise adds that of Duc d'Aubigny in the peerage of France.

But though honoured by the king, and flattered by the court, the Duchess of Portsmouth was far from enjoying uninterrupted happiness; inasmuch as her peace was frequently disturbed by jealousy. The principal cause of her uneasiness during the first five years of her reign was the king's continued infatuation for Nell Gwynn; now, by reason of the elevated position she enjoyed, styled Madam Ellen. This "impudent comedian," as Evelyn calls her, was treated by his majesty with, extreme indulgence and royal liberality. In proof of the latter statement, it may be mentioned that in less than four years from the date of her first becoming his mistress, he had wantonly lavished sixty thousand pounds upon her, as Burnet affirms. Moreover, he had purchased as a town mansion for her "the first good house on the left-hand side of St. James's Square, entering Pall Mall," now the site of the Army and Navy Club; had given her likewise a residence situated close by the Castle at Windsor; and a summer villa located in what was then the charming village of Chelsea. To such substantial gifts as these he added the honour of an appointment at court: when the merry player was made one of the ladies of the privy chamber to the queen. Samuel Pegg states this fact, not generally known, and assures us he discovered it "from the book in the lord chamberlain's office."

From her position as the king's mistress, Madam Ellen moved on terms of perfect equality with the Duchess of Portsmouth's friends—supping with my Lady Orrery, visiting my Lord Cavendish, and establishing a friendship with the gay Duchess of Norfolk. This was a source of deep vexation to the haughty Frenchwoman; but Nell Gwynn's familiarity with the king was a cause of even greater mortification. Sir George Etherege records in verse when the monarch was "dumpish" Nell would "chuck the royal chin;" and it is stated that, mindful of her former conquests over Charles Hart and Charles Lord Buckley, it was her habit to playfully style his majesty "Charles the Third." Her wilfulness, wit, and beauty enabled her to maintain such a strong hold upon the king's heart, that he shared his time equally between her and the Duchess of Portsmouth. Indignant that a woman from the playhouse should receive such evidences of the royal affection, her grace lost no opportunity of insulting Nell, who responded by mimicry and grimaces, which threw those who witnessed the comedy into fits of laughter, and covered the wrathful duchess with confusion.

But though the light-hearted actress frequently treated disdain with ridicule, she could occasionally analyze the respective positions held by herself and the duchess with seriousness, Madame de Sevigne tells us, Nell would reason in this manner: "This duchess pretends to be a person of quality: she affirms she is related to the best families in France, and when any person of distinction dies she puts herself in mourning. If she be a lady of such quality, why does she demean herself to be a courtesan? She ought to die with shame. As for me, it is my profession. I do not pretend to anything better. The king entertains me, and I am constant to him at present. He has a son by me; I contend that he ought to acknowledge him—and I am well assured that he will, for he loves me as well as the duchess."

To have her son ennobled, and by this means raise him to an equality with the offspring of her grace, became the desire of Nell Gwynn's life. To her request that this favour might be granted, the king had promised compliance from time to time, but had as frequently postponed the fulfilment of his word. At last, weary of beseeching him, she devised a speech which she trusted might have the desired effect. Accordingly, when the monarch came to see her one day, he found her in a pensive mood, playing with her pretty boy; and the lad, being presently set upon his feet, he promptly tottered down the room, whereon she cried out to him, "Come here, you little bastard!" Hearing this word of evil import applied to his son, the monarch begged she would not use the expression, "I am sorry," said she regretfully, "but, alas, I have no other name to give him!" His majesty took the hint, and soon after bestowed on him that of Charles Beauclerk, and created him Baron of Heddington, in Oxon, and Earl of Burford in the same county; and finally, when he had reached the age of ten years, raised him to the dignity of Duke of St. Albans.

After a reign of five years in the court of the merry monarch, her Grace of Portsmouth was destined to encounter a far more formidable rival than Nell Gwynn, in the person of the Duchess of Mazarine. This lady, on her arrival in England in 1675, possessed most of the charms which had rendered her notable in youth. To the attraction they lent was added an interest arising from her personal history, in which King Charles had once figured, and to which fate had subsequently added many pages of romance.