Thomas Aquinas was born in his family's castle around the end of 1224, near Aquino. He was the youngest of seven kids that his family had. His father was a relative of Frederick II, Emperor of Sicily. In 1230, his parents presented him as an oblate to the Benedictine Abbey at Monte Cassion (he was offered up for the religious life). In 1239, the conditions became dangerous, when the Pope and Frederick II had a quarrel, and Aquinas returned to his parent's home for a couple of months. Then, he went to study liberal arts at the University of Naples. His father died at Christmas time in 1243, and Thomas joined the Dominican Order at Naples.

In 1248, he went with the famous Dominican scholar Albert the Great to Cologne. Albert valued the many writings of Aristotle and passed them on to Aquinas. Aquinas was very large, physically, and quiet. Many of the other students called him "the dumb ox", and Aquinas said that one day the entire world would be listening to the bellowing of this "dumb ox". In 1251, Aquinas was ordained a priest at Cologne, and he went to Paris to continue his studies. In the spring of 1256, he received his licentiate in theology and became a master of theology, and became a teacher at the University of Paris.

From 1256 to 1259, Aquinas served as regent master of theology at Paris. In 1259 he was appointed Preacher General in Italy. In 1265, he was sent to Rome to serve as Regent Master.

In November of 1268, he returned to the University of Paris. Classes were suspended in early 1272, and in the spring of 1272 he returned to Naples to start a Dominican house of studies. In December of 1273, he had an experience in church, in which he says that during mass he felt that all he had written was insignificant, and he ceased writing. In 1274, Pope Gregory X summoned him to the Council of Lyons in France, and on the way he fell ill, and stopped at his sister's house. He died in a Cistercian monastery at Fossanuova on March 7, 1274. Exactly three years after his death the Bishop of Paris condemned 219 propositions, including Aquinas's. In 1278, a General Chapter of Dominicans upheld Aquinas's views.