So the biographer Phocas ends his invocation to the muse Clio that precedes his hexameter Life of Virgil. A grammarian and teacher at Rome, Phocas likely dates to the late fourth or fifth century. His Vita, with a twenty-four-line preface in sapphics, a concluding lacuna, and textual problems in lines 75–83, is the only example we have of an ancient Virgilian biography written in verse.

Scholarship on Phocas has consistently traced his Vita back to earthlier sources than Clio. These are the Virgilian biographies of Suetonius and the fourth-century CE Aelius Donatus, who, the evidence is strong, essentially reproduced the now lost Suetonian text. (The abbreviation VSD conventionally designates Donatus's work, with its presumed origins in Suetonius.) While some identify Suetonius as Phocas's model or maintain an agnostic stance with regard to which of his precursors Phocas used, the majority position is that he relied upon his fellow late-antique biographer Donatus. Lending credence to this viewpoint is Phocas's treatment of how Virgil got caught up in the land confiscations that followed the Battle of Philippi (92–113).