"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" (Wikipedia article on Aelius Donatus, accessed 01-15-2011).