Unfortunately, almost nothing can be said about the life of Aelius Festus Apthonius, author of the extensive treatise de metris, which in the manuscript tradition is associated with the Ars grammatica of Marius Victorinus. His name is preserved for us by the subscriptio that closes the fourth book of the work: AELII FESTI APTHONII V(IRI) P(ERFECTISSIMI) DE METRIS OMNIBUS EXPLIC. LIB. IIII. On the correctness of the spelling Apthonius (and not Aphtonius), W. Schulze (Orthographica, Rome 1958, pp. 38 ff.) expressed himself at the time. It has been suggested that he was of African origin, on the basis that his auctores include Juba, Terentianus Maurus and Marius Victorinus, but there is no certain data for this claim. The title of vir perfectissimus, an honour bestowed on the highest ranks of the equestrian order by Antoninus Pius until the Constantinian reform, at least suggests, with a wide margin of safety, that it can be assigned to the first half of the 4th century. [D. Di Rienzo]