(Often called "The Peripatetic of Thubursicum" - Thubursicum probably being his birthplace, in Numidia)
Numidian/Roman author, active in the early 4th century.
As a grammarian and lexicographer, Nonius Marcellus is chiefly known for his encyclopaedia-like magnum opus, the De compendiosa doctrina (20 vols.) - a collation of various quotations from other classical authors (in particular, Aulus Gellius and Verrius Flaccus), with commentary. The Doctrina deals mainly with language (grammar and lexicography), but includes excursions into various other, antiquarian, subjects.
Although it contains little original material, the Doctrina preserves many fragments of other works where the original has been lost. As such, it is an invaluable aid to classical scholars.
Later Latin grammarians (e.g. Priscian and Fulgentius) borrowed heavily from Nonius Marcellus' work. In the 5th century, a revised and annotated edition was published by one Julius Tryphonianus Sabinus (otherwise unknown).