Born in Paris, Etienne Gilson was educated at the University of Paris. He became professor of medieval philosophy at the Sorbonne in 1921, and in 1932 was appointed to the chair in medieval philosophy at the College de France. In 1929 he cooperated with the members of the Congregation of Priests of St. Basil, in Toronto, Canada, to found the Pontifical Institute of Medieval Studies in association with St. Michael's College at the University of Toronto. Gilson served as professor and director of studies at the institute. Like his fellow countryman Jacques Maritain, Etienne Gilson was a neo-Thomist for whom Christian revelation is an indispensable auxiliary to reason, and on faith he accepted Christian doctrine as advocated by the Roman Catholic church. At the same time, like St. Thomas Aquinas, he accorded reason a wide compass of operation, maintaining that it could demonstrate the existence of God and the necessity of revelation, with which he considered it compatible. Why anything exists is a question that science cannot answer and may even deem senseless. Gilson found the answer to be that "each and every particular existing thing depends for its existence on a pure Act of existence." God is the supreme Act of existing. An authority on the Christian philosophy of the Middle Ages, Gilson lectured widely on theology, art, the history of ideas, and the medieval world.