St. Thomas Aquinas, OP (1225 – 7 March 1274) was an Italian Dominican friar and priest who was an influential philosopher, theologian and jurist in the tradition of scholasticism; he is known as the Doctor Angelicus, the Doctor Communis, and the Doctor Universalis. The name Aquinas identifies his ancestral origins in the county of Aquino in present-day Lazio, Italy. Among other things, he was a prominent proponent of natural theology and the father of a school of thought (encompassing both theology and philosophy) known as Thomism. He argued that God is the source of both the light of natural reason and the light of faith. He has been described as “the most influential thinker of the medieval period” and “the greatest of the medieval philosopher-theologians”. His influence on Western thought is considerable, and much of modern philosophy is derived from his ideas, particularly in the areas of ethics, natural law, metaphysics, and political theory.
Unlike many currents in the Catholic Church of the time, Thomas embraced several ideas put forward by Aristotle—whom he called “the Philosopher”—and attempted to synthesize Aristotelian philosophy with the principles of Christianity.