The theological system of St. Thomas Aquinas (1224/25-1275), embodied in his Summa Theologica. Adapting Aristotle's philosophy to Christian revelation, Thomas defined God as Primary Being, in whom alone essence and existence are one. The Three Persons subsist in the divine Essence, with which each is identical. Creation is a going out of the creature from God. The Incarnation of the Word, the institution of the church, the sacraments, the theological virtues of faith, hope, and charity, and the moral virtues are the normal means of the creature's return to God. Salvation is entirely God's gift. Eternal beatitude is given in a face-to-face vision of God in heaven. The English theologian Richard Hooker made use of Thomism. In 1879 Pope Leo XIII made Thomism the chief instrument of theological education in Roman Catholic seminaries.
Glossary definitions provided courtesy of Church Publishing Incorporated, New York, NY,(All Rights reserved) from "An Episcopal Dictionary of the Church, A User Friendly Reference for Episcopalians," Don S. Armentrout and Robert Boak Slocum, editors.