Ahighly desirable guest. What could be a more delicious way to be described? And by Nancy Mitford no less. Long after her death, Jeanne Antoinette Poisson received this delectable sobriquet from Mitford, who wrote that Poisson’s innate desirability stemmed from “her looks and elegance, and possessing as she did that intense love of life, and interest in human beings, which is perhaps the basis of what we variously call charm, sex appeal or fascination.” Bright Young Thing that she was, Nancy Mitford knew a thing or two about people in possession of charm and fascination (not to mention fascism, but that’s another story). A friend to Evelyn Waugh, Mitford was born to privilege, money and dysfunction, and used her intricate knowledge of upper class (or “U”) curiosities as both a novelist and a biographer. Her nonfiction works included historical accounts of the colorful lives of Voltaire, Louis XIV known as The Sun King, and the greatest mistress to sleep her way to the top of Versailles’ pecking order, Jeanne Poisson — the Madame de Pompadour.

When the aristocracy still ruled France, when marriage was for duty and mistresses were for pleasure (and power), the flirtatious charged, mad-cap meeting of Jeanne Antoinette and King Louis XV was legend. The initially low-born Jeanne may have already been married, but the opportunity to ensnare the king was too enticing. “Every pretty woman in the Ile de France nurtured a conviction that she would carry off the prize,” Mitford wrote. “Such was the prestige of the monarch in those days, so nearly was he considered a god, that very little shame attached to the position of his mistress.” Not to mention an apartment in Versailles and a fortune paid to the lucky woman’s family. Jeanne caught his attention purposely blocking off his carriage with her conspicuously feminine pink phaeton, and he in turn made his move by inviting her to a masked ball, where he met her in disguise while she dressed as the Roman lunar goddess of the hunt, Diana. Louis, Mitford wrote, “had never known that particularly delightful relationship of sex mixed with laughter.”

Her feminine tastes and patronage to artists help cultivate the Rococo decorative movement, and her best-known portraits were commissions by François Boucher. The 18th century French painter was the Rococo master of voluminous silk gowns, plump, milky skin, rounded, soft breasts and buttocks, wild swans, fluttering pink ribbons and periwinkle blue skies. Romantic and erotic, pastoral and mythical, Boucher crafted pastel paradise on the canvas, and his portraits of Jeanne feature her in blissful rule as the court’s maîtresse-en-titre.

“Promenades on Paper: Eighteenth-Century French Drawings from the Bibliothèque nationale de France” with selected works by François Boucher opens at the Clark Art Institute in Williamstown, Mass., on Dec. 17.

Portrait of Madame de Pompadour by François Boucher

Portrait of Madame de Pompadour by François Boucher

Portrait of Madame de Pompadour by François Boucher