St. Thomas Aquinas was a prominent Italian Dominican friar, philosopher, and theologian of the Catholic Church in the 13th century. He is best known for his influential works in natural theology, ethics, and metaphysics, particularly his synthesis of Aristotelian philosophy with Christian theology. His most famous work, "Summa Theologica," is considered one of the greatest achievements in Western philosophy and theology. St. Thomas Aquinas is recognized as a Doctor of the Church and is celebrated as a key figure in the development of Christian thought.