=The Predecessors of Aquinas.= Many distinguished names stand at the close of the Transitional Period and the beginning of the Classic Period. These express the transitional character of the thought of the threshold of this time. They show, like Abelard, the tendency toward rationalism. Alexander of Hales (d. 1264), William of Aubergne (d. 1249), Vincent of Beauvais (d. 1246), Albert of Bollstaedt, called Albertus Magnus (d. 1280), show the influence of the new Aristotelian science. Albert was the teacher of Thomas Aquinas. The attempt of Thomas to form a theological system for the church was anticipated by the so-called _Sums_ of the twelfth century, of which the work of Peter the Lombard was the model. The four books of _Sums_ of Peter were collections of opinions of the Fathers on questions of dogma. They show the influence of Aristotle and the method of Abelard. The _Sums_ of Peter became for several centuries the text-book of the schools and the subject of innumerable commentaries. It was the core of Classic scholastic literature, and around it grew up the problems of metaphysics and psychology. =The Life of Thomas Aquinas (1224–1274).――The Founder of the Dominican Tradition.= Thomas belonged to a noble house which was related to the royal family. He studied in the University of Naples, but at the age of nineteen, upon resolving to enter the Dominican order, he was captured and kept a prisoner by his brothers. After two years he made his escape, and, his family having consented to his taking orders, he went to Cologne under the instruction of Albert. He was then sent to Paris, where he obtained his degree in 1257. He was a successful lecturer at Paris until 1261, when he was called by the Pope to teach philosophy in Rome, Bologna, and Pisa. During this period he composed his greatest work, _Summa Theologiae_. He declined preferment and finally resided at Naples. He always enjoyed the highest consideration of the church authorities. Thomas, the founder of the “Dominican tradition,” was the first to formulate Christian Aristotelianism and to draw for the church the line between the realms of reason and faith. He did not so much create doctrine as he transformed and assimilated it. The sources from which he drew were many: the Scriptures, the Fathers, Greek philosophy, and the teaching of contemporary Arabians and Jews. If, as some historians maintain, he was not a thinker of the first rank, he at least relieved the church from a delicate situation by means of a conciliating theology. Certainly his predecessors and contemporaries stand eclipsed by him. He satisfied the mediæval demand for order and he prevented deterioration in the church doctrine. He did not rise above his age, although he stood at the head of its intellectual movement. He was, on the contrary, the most perfect expression of scholasticism, and he was affectionately regarded as _doctor angelicus_ and again as _doctor universalis_.