Works on grammar were written long before modern syntax came about; the Aṣṭādhyāyī of Pāṇini (c. 4th century BC) is often cited as an example of a premodern work that approaches the sophistication of a modern syntactic theory.[2] In the West, the school of thought that came to be known as "traditional grammar" began with the work of Dionysius Thrax.
For centuries, work in syntax was dominated by a framework known as grammaire générale, first expounded in 1660 by Antoine Arnauld in a book of the same title. This system took as its basic premise the assumption that language is a direct reflection of thought processes and therefore there is a single, most natural way to express a thought. (That natural way, coincidentally, was exactly the way it was expressed in French.)
However, in the 19th century, with the development of historical-comparative linguistics, linguists began to realize the sheer diversity of human language and to question fundamental assumptions about the relationship between language and logic. It became apparent that there was no such thing as the most natural way to express a thought, and therefore logic could no longer be relied upon as a basis for studying the structure of language.
The Port-Royal grammar modeled the study of syntax upon that of logic (indeed, large parts of the Port-Royal Logic were copied or adapted from the Grammaire générale[3]). Syntactic categories were identified with logical ones, and all sentences were analyzed in terms of