Caption:
Rene Descartes (1596-1650) French philosopher and mathematician, showing some of the principal events of his life, including the death of his illegitimate daughter, Francine, at the age of 5 (1640), and as teacher to Queen Christina of Sweden (1649-1650). Engraving by Nicolas Ponce 1746-1831) from "Les Illustres Francais". (Photo by: Universal History Archive/UIG via Getty Images)