St Thomas Aquinas–known in the Church as the Angelic or the Common Doctor–is one of the Church’s greatest theologians and philosophers. Although Thomas died at the tender age of 49, outlived by his mentor Albert the Great, he left behind him a corpus of theological work which changed the face of the Church forever.
Born in 1225 in Aquino, a town in Lazio near the famous Benedictine Abbey of Monte Cassino, St Thomas was destined by his family to become a Benedictine monk, but the scholarly and single-minded young man was determined to join the Dominicans. The Order, founded by St Dominic and approved by Pope Honorius III less than 10 years before Thomas’s birth, marked a radical change from the Church’s monastic tradition with its mendicant preaching friars. Setting himself against his family’s wishes, St Thomas prevailed and joined the Dominican Order where he was sent to the great University of Paris, the centre of learning in the Medieval world. It is here he would have first encountered St Albert the Great. Thanks to Islamic scholarship, the medieval world saw an influx of classical scholars and texts, including the work of Aristotle. Much of St Thomas’s work was involved in tying the Christian tradition to the classical tradition which preceded it and incorporating an Aristotelian world-view into Christian philosophy and theology. For St Thomas, Natural Law was a key point of focus for his academic work.
From Paris, St Thomas, who was described by contemporaries as an ox, went to Cologne to teach and back to Paris again. Then, obedient, he went to Orvieto near Naples, before being sent to Rome to set up a Dominican Studium at Santa Sabina. While he was there he started writing his most famous and most important work the Summa Theologica. He was sent back to Paris to be regent of the university at a particularly difficult time in the University’s life, during which the different Aristotelian interpretations were being challenged, disputed and condemned. In 1272 he returned to Italy where he eventually died in 1274.
And you can download the Summa for free from Project Gutenberg.