Gabrielle Emilie Le Tonnelier de Breteuil, marquise du Châtelet (17 December 1706, Paris - 10 September 1749, Lunéville) was a French mathematician, physicist, and author during the Age of Enlightenment. Her crowning achievement is considered to be her translation and commentary on Isaac Newton's work Principia Mathematica. The translation, published ten years after her death in 1759, is still considered the standard French translation. Read more
As a girl, Emilie de Breteuil lived with her family overlooking the Tuileries gardens in Paris, in an apartment with 30 rooms and 17 servants. But although her brothers and sisters turned out as might be expected, Emilie was different, as her father wrote: "My youngest flaunts her mind, and frightens away the suitors."
Despite her father's fears, Emilie had many suitors. At the age of 19, she chose one of the least objectionable courtiers as a husband. He was a wealthy soldier named du Châtelet who would conveniently be on distant campaigns much of the time. It was a pro forma arrangement, and in the custom of the time, her husband accepted her having affairs while he was away.
When she was a 27-year-old mother of three, du Châtelet began perhaps the most passionate affair of her life—a true partnership of heart and mind. Her lover, the writer Voltaire, recounted later, "In the year 1733 I met a young lady who happened to think nearly as I did." She and Voltaire shared deep interests: in political reform, in the fun of fast conversations, and, above all, in advancing science as much as they could.