Priscian

Priscian, or the Grammar, relief from the bell tower of Florence by Luca della Robbia

Priscianus Caesariensis (fl. AD 500), commonly known as Priscian (/ˈprɪʃən/ or /ˈprɪʃiən/), was a Latin grammarian and the author of the Institutes of Grammar, which was the standard textbook for the study of Latin during the Middle Ages. It also provided the raw material for the field of speculative grammar.