St. Thomas Aquinas was a 13th-century Italian philosopher and theologian, known for his influential works in the field of scholasticism. He sought to reconcile faith and reason, arguing that both could lead to truth. His most famous work, the Summa Theologica, explores various aspects of Christian theology, ethics, and the nature of God. Aquinas is often regarded as one of the greatest thinkers in the Catholic Church, and his ideas have shaped Christian philosophy for centuries. He introduced the concept of the "Five Ways" to prove the existence of God, which remain significant in religious discussions today.