Émilie du Châtelet

She was featured in today's Google doodle.

Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet (French pronunciation: [emili dy ʃɑtlɛ] (listen); 17 December 1706–10 September 1749) was a French natural philosopher and mathematician during the early 1730s until her death due to complications during childbirth in 1749. Her most recognized achievement is her translation of and commentary on Isaac Newton's 1687 book Principia containing basic laws of physics. The translation, published posthumously in 1756, is still considered the standard French translation today. Her commentary includes a contribution to Newtonian mechanics—the postulate of an additional conservation law for total energy, of which kinetic energy of motion is one element. This led to her conceptualization of energy as such, and to derive its quantitative relationships to the mass and velocity of an object.

Her philosophical magnum opus, Institutions de Physique (Paris, 1740, first edition), or Foundations of Physics, circulated widely, generated heated debates, and was republished and translated into several other languages within two years of its original publication. She participated in the famous vis viva debate, concerning the best way to measure the force of a body and the best means of thinking about conservation principles. Posthumously, her ideas were heavily represented in the most famous text of the French Enlightenment, the Encyclopédie of Denis Diderot and Jean le Rond d'Alembert, first published shortly after du Châtelet's death. Numerous biographies, books and plays have been written about her life and work in the two centuries since her death. In the early 21st century, her life and ideas have generated renewed interest.

Émilie du Châtelet had, over many years, a relationship with the writer and philosopher Voltaire.

From Wikipedia. 

Go read the biography portion of the linked entry. Her life was quite remarkable. For example, "by the age of twelve she was fluent in Latin, Italian, Greek and German; she was later to publish translations into French of Greek and Latin plays and philosophy. She received education in mathematics, literature, and science. Du Châtelet also liked to dance, was a passable performer on the harpsichord, sang opera, and was an amateur actress. As a teenager, short of money for books, she used her mathematical skills to devise highly successful strategies for gambling."

Her life is also a reminder of the reality that in the 18th century even the scientifically minded nobility (her parents were minor nobles and part of the French King's court, her husband was a high ranking noble, and later in life she had affairs first with Voltaire, and then with a leading French poet) was not free of widespread infant and child and maternal mortality. Her experience in this regard was the norm, and not unusually tragic (see also, e.g., Euler).

Two of her five brothers died in childhood and two more died young. 

She gave birth four times. Her third and fourth children died as infants and she died giving birth to her fourth child at age forty-two.

Also:

On 12 June 1725, she married the Marquis Florent-Claude du Chastellet-Lomont. Her marriage conferred the title of Marquise du Chastellet. Like many marriages among the nobility, theirs was arranged. As a wedding gift, the husband was made governor of Semur-en-Auxois in Burgundy by his father; the recently married couple moved there at the end of September 1725. Du Châtelet was eighteen at the time, her husband thirty-four.