Thomas Aquinas (1225-1274) was an Italian theologian, philosopher, and Dominican friar who made significant contributions to the development of Christian theology and Western philosophy. He is best known for his magnum opus, "Summa Theologica," which sought to integrate the teachings of the Bible with the rational principles of Aristotle's philosophy. Aquinas emphasized the compatibility of faith and reason, asserting that both could lead to a greater understanding of God and the world. His natural law theory posited that moral principles could be derived from human nature and reason, making them universally applicable.