Aelius Donatus

Aelius Donatus (English: ; fl. mid-fourth century AD) was a Roman grammarian and teacher of rhetoric, whose works on Latin grammar were very widely used in the teaching of Latin during the Middle Ages. His Ars minor was the standard elementary introduction to grammar during that period.

Notable works: Ars grammatica, Commentarius in Terentii comoedias

Source: Wikipedia — https://en.wikipedia.org/wiki/Aelius_Donatus