Charles Marie de La Condamine was a French explorer, geographer, and mathematician. He spent ten years in territory which is now Ecuador, measuring the length of a degree of latitude at the equator and preparing the first map of the Amazon region based on astro-geodetic observations. Furthermore he was a contributor to the Encyclopédie.

François-Marie Arouet, known by his nom de plume M. de Voltaire, was a French Enlightenment writer, philosopher (philosophe), satirist, and historian. Famous for his wit and his criticism of Christianity and of slavery, Voltaire was an advocate of freedom of speech, freedom of religion, and separation of church and state.