The Spanish Jesuit Juan de Mariana (1536-1624), a man of critical insight, accuracy, and courage, is well known as a historian and political thinker.

Juan de Mariana was born in Talavera de la Reina in the old kingdom of Toledo. He joined the Jesuits in 1554 and studied at the University of Alcalá de Henares. In 1561 he went to Rome, where he taught theology to, among other pupils, Robert Bellarmine, who was to become the most famous cardinal of his time. From there he went to Sicily, and in 1569 he was sent to Paris. His lectures on St. Thomas Aquinas were a great success, but in 1574, pleading ill health, he obtained permission to return to Spain. He retired to the Jesuit house in Toledo, where his literary activity was occasionally, and rudely, interrupted by the outside world. He died there on Feb. 16, 1624.

In Mariana's lifetime his writings had...