The key to the philosophy and history of Bulgarian linguistics is hidden in the Bulgarian syntactic tradition. Today's grammatical heritage lies within the field of European syntactic tradition and can be viewed as two separate branches of the Tree of Grammatical Knowledge – one growing out of ancient tradition and developing in the Slavia Orthodoxa culture as practical philology, while the other also grew out of the ancient tradition and developed in the field of Western European academic circles, where grammar was taught as one of the Seven Liberal Arts (Septem Artes Liberales). We can distinguish two grammatical prototypes: Plato's definition of a sentence: NV (Man learns), and Aristotle's syllogism: Subject – Copula – Predicate (The earth is round).