So far we have reviewed the contributions of ancient Greece, Rome, and the early Middle Ages to the history of universal grammar and second language learning. In the last centuries of the first millennium, Insular and Carolingian scholars adapted traditional grammatical materials to the needs of early medieval L2 learners of Latin, producing the first foreign language grammars. The Greek philosophical literature was largely inaccessible then, but when Aristotle’s works were rediscovered in the twelfth and thirteenth centuries, discussion of universal grammar flourished. Medieval grammarians modelled their notion of universal grammar on the properties of Latin, their L2. Moreover, they derived much of their conceptual apparatus and metalinguistic vocabulary from the Greco-Roman grammatical tradition. Thus the contributions of Greece, Rome and the immediate post-classical world converged in the Middle Ages.