Aelius Donatus (English pronunciation: /doʊˈneɪtəs/; fl. mid-fourth century AD) was a Roman grammarian and teacher of rhetoric. St. Jerome states in Contra Rufinum 1.16 that Donatus was his tutor.
He was the author of a number of professional works, of which several are extant:
- A partly incomplete commentary on the playwright Terence is compiled from other commentaries, but probably not in its original form.
- His Life of Virgil is thought to be based on a lost Vita by Suetonius, together with the preface and introduction of his commentary on Virgil's works. A greatly expanded version of Servius' commentary exists, however, which is supplemented with frequent and extensive extracts from what is thought to be Donatus' commentary on Virgil.
- His Ars grammatica, especially the section on the eight parts of speech, though possessing little claim to originality, and evidently based on the same authorities which were used by the grammarians Charisius and Diomedes, attained such popularity as a schoolbook that, in the Middle Ages, he became the eponym for a rudimentary treatise of any sort, called a donet. When books came to be printed in the 15th century, editions of the little book were multiplied to an enormous extent. It is also the only purely textual work to be printed in blockbook form (cut like a woodcut, not using movable type). It is in the form of an Ars Minor, which only treats of the parts of speech, and an Ars Major, which deals with grammar in general at greater length.
Donatus was a proponent of an early system of punctuation, consisting of dots placed in three successively higher positions to indicate successively longer pauses, roughly equivalent to the modern comma, colon, and full stop. This system remained current through the seventh century, when a more refined system due to Isidore of Seville gained prominence.
Donatus invented the system whereby a play is made up of three separate parts: protasis, epitasis, and catastasis.
Aelius Donatus should not be confused with Tiberius Claudius Donatus, also the author of a commentary (Interpretationes) on the Aeneid, who lived about 50 years later.