St. Augustine, Boethius, and others, Christianized the classical curriculum. By the early middle-ages the so-called seven liberal arts were celebrated by the leading thinkers of Europe. The trivium (grammar, rhetoric, dialectic) gave access to reality via linguistic signs; the quadrivium (arithmetic, geometry, music, astronomy), through mathematics. The trivium taught the mind to grasp order and beauty particularly as manifest in qualities, the quadrivium, through quantities.
“As to those who…make no account of the liberal and fine arts, or are incapable of being instructed in them – I know not how I could call them happy as long as they live among men.”
-St. Augustine (354-430), On Order 2.9.26.
“These seven [arts] they considered so to excel all the rest in usefulness that anyone who had been thoroughly schooled in them might afterward come to a knowledge of the others by his own inquiry and effort rather than by listening to a teacher. For these, one might say, constitute the best instruments, the best rudiments, by which the way is prepared for the mind’s complete knowledge of philosophic truth. Therefore they are called by the name trivium and quadrivium, because by them, as by certain ways (viae), a quick mind enters into the secret places of wisdom.”
-Hugh of St. Victor (1096-1141), Didascalicon: A Medieval Guide to the Liberal Arts, 3.3.
“How can one have a classical curriculum without reading the classics? The answer is that one cannot have a classical curriculum in the fullest and most perfect sense until one has students who are capable of the kind of abstract thinking required for a study of the subjects of the Trivium: grammar, logic, rhetoric; and the Quadrivium: arithmetic, geometry, music and astronomy.”
-Laura Berquist, Leading Catholic Educator and author of Designing Your Own Classical Curriculum, from her Appendix.