Madame de Tencin
Claudine Alexandrine Guérin de Tencin, Baroness of Saint-Martin-de-Ré was a French salonist and author. She was the mother of Jean le Rond d'Alembert, who later became a prominent mathematician, philosophe and contributor to the Encyclopédie, though she left him on the steps of the Church of Saint-Jean-le-Rond on the north side of Notre Dame cathedral a few days after his birth in November 1717.