Gabrielle Émilie Le Tonnelier de Breteuil, Marquise du Châtelet

Born on December 17 1706 as a part of the lesser nobility; therefore she was not destined for the glamorous life we usually connect with French courtiers. Already from her early childhood Gabrielle Émilie was used to the society of learned thinkers who came to visit once every week to attend the salon her father kept - undoubtedly Gabrielle Émilie's apple did not fall far from the trunk.
Unlike most men of his time, her father soon realised that his daughter had a remarkable intelligence and was quick to arrange for an education usually out of reach for a girl. Her mother too seems to have been encouraging her daughter in her lessons in astronomy and even fencing and riding.

The lessons soon paid off and by the age of 12 Gabrielle Émilie was fluent in not just her native French but German, Greek, Italian and Latin as well. However intelligent, it was still undisputed that Gabrielle Émilie was to marry - this happened in June 1725 when she was married to the Marquis Florent-Claude du Chastellet-Lomont (Gabrielle was 19 years old while her new husband was 34). The marriage produced three children.

Marriage-life had kept Gabrielle Émilie away from her studies for 7 years but when she was 26 years old she returned to the world of academics. This was the time when Voltaire re-entered her life (according to the philosopher himself they had first met in 1729 through her father's salon). In Voltaire Gabrielle Émilie had found an intellect to match her own and - with her husband's permission - she invited Voltaire to live in her country house where they would spent many days together. It was actually Voltaire who changed the spelling of her last name from Chastellet to Châtelet. It was from here that Gabrielle Émilie published her scientific articles and contributed to Voltaire's work. Whether they were lovers is unknown but it seems unlikely.
With Voltaire she had a relationship of healthy competition and mutual respect. She would become the first woman to have an article published by the Academy of Sciences.

It would appear that Gabrielle Émilie did not spent much time with her husband after she moved to her country house. In 1748 it became widely known that Gabrielle Émilie had taken the poet Jean-François de Saint-Lambert as her lover. And as fate would have it she became pregnant with his child which greatly disturbed her - she reputedly wrote to her friend that she feared for her health. She went into labour on 3 September 1749 and gave birth to a daughter. One week later Gabrielle Émilie died at the age of 42 years old - what she might have achieved had she lived longer will always be a mystery.