The trivium is implicit in "De nuptiis Philologiae et Mercurii" ("On the Marriage of Philology and Mercury") by Martianus Capella, but the term was not used until the Carolingian Renaissance, when it was coined in imitation of the earlier quadrivium. Grammar, logic, and rhetoric were essential to a classical education, as explained in Plato's dialogues. The three subjects together were denoted by the word "trivium" during the Middle Ages, but the tradition of first learning those three subjects was established in ancient Greece. Contemporary iterations have taken various forms, including those found in certain British and American universities (some being part of the Classical education movement) and at the independent Oundle School in the United Kingdom.