Charles-Irénée Castel de Saint-Pierre, French philosopher and author (d. 1743)

Charles-Irénée Castel, abbé de Saint-Pierre (18 February 1658 – 29 April 1743) was a French author whose ideas were novel for his times. His proposal of an international organisation to maintain peace was perhaps the first in history, with the possible exception of George of Poděbrady's Tractatus (1462–1464). He influenced Rousseau and Kant.