The exact date of Aquinas’ birth is uncertain, though it probably took place in or about 1225. He came of an originally Lombard family and was born at the castle of Roccasecca near the small town of Aquino, which lies between Naples and Rome. At a very early age, he was sent to the abbey of Monte Cassino for elementary schooling and, in about 1239, he went, as a student, to the University of Naples, which had been founded by Emperor Frederick II in 1224. While at Naples, he entered the Dominican Order, and this action aroused opposition on the part of his family, who shut him up for a time under guard. On regaining his freedom, he went north to pursue his studies under Albert the Great, also a Dominican, at Paris and Cologne. After returning from Cologne to Paris in 1252, he lectured, according to custom, first on the Scriptures, from 1252 to 1254, and then on the Sentences of Peter Lombard, from 1254 to 1256. In the medieval university, the practice of explaining and commenting on a text occupied a prominent place, and the Libri quattuor sententiarum (Four Books of Opinions), a mainly theological work compiled by Peter Lombard in the twelfth century, continued to be used as a textbook until the end of the sixteenth century. The leading theologians and philosophers of the thirteenth and fourteenth centuries, including Aquinas, Duns Scotus, and William of Ockham, lectured and wrote commentaries on it.
In 1256, Aquinas became a regular professor of theology, occupying one of the two chairs allotted to the Dominicans at Paris, though it was not until the following year that his appointment was fully recognized by the university, the reason for this delay being the dispute between the secular clergy and the new religious Orders. From 1259 to 1269, he was in Italy, where he taught successively at Anagni, Orvieto, Rome, and Viterbo. In 1269, he resumed his lecturing at Paris but, in 1272, he went to Naples to organize the Dominican house of theological studies. Two years later, he was summoned by Pope Gregory X to take part in the Council of Lyons, but he died on the way, on March 7, 1274.
A rather wandering life of this kind can hardly have been altogether congenial to a scholar and thinker. But his unremitting application to study and writing in all possible circumstances enabled him to produce an astonishing number of works in his short life of some forty-nine years. He was, we are told, somewhat absent-minded, in the sense that his absorption in his thoughts led him, sometimes, to forget his surroundings. But, he was noted for his kindness and, in spite of his devotion to study, he found time for regular preaching. As a priest and friar, he was, in every way, exemplary and, at any rate, towards the end of his life, he enjoyed mystical experiences. In December, 1273, after an experience while saying Mass, he suspended his work on the third part of his Summa theologica [A Summary of Theology], telling his secretary that he had reached the end of his writing and giving as his reason the fact that “all I have written seems to me like so much straw compared with what I have seen and with what has now been revealed to me”. He was canonized on July 18, 1323.
From: Aquinas by F. C. Copleston (Baltimore: Penguin Books, 1955), pp. 9-10.