c. 810-c. 877

Irish theologian and philosopher who in his De divisione naturae (862-66) put forth the theory that Mercury, Venus, Mars, and Jupiter all orbit the Sun—an extraordinarily daring notion in his time. Erigena, who taught at the court of French king Charles II (the Bald) near Laon, also wrote a major work, De predestinatione (851), on questions of predestination, salvation, and free will. De divisione, the most important of his writings, marked an early attempt to reconcile non-religious views on Earth's origins (in this case, the Neoplatonist theory of emanationism) with Christian creationism. His work gained great influence, but in 1225 Pope Honorius II condemned it due to its tone of pantheism, or the idea that God and the natural laws of the universe constitute a single entity.