Isidore composed the De viris illustribus, the collection of short biographies of the Christian writers following the example of Jerome and Gennadius of Marseilles. The date of composition is uncertain. Some scholars arguing on the basis of allegedly chronological order of Isidore`s work in the Renotatio librorum of Braulio of Saragossa, dated the De viris illustribus to 616-619 (Schutte 1902: 7) or to 615-618 (Aldama 1936). Dzialowski who rejected the chronological order in the Renotatio thought that the De viris illustribus were written between 610-615. J.-C. Martin (2000) also rejects the chronological order in the Renotatio, in result also the dating of Aldama. He notices that in the De viris illustribus Isidore mentions the homilies on the Gospel of Gregory the Great, but confesses that he had not yet read them. But we know that he already knew them while writing the Sententiae. Martin, in his edition of the Life of Desiderius by Sisebutus dated to 615-617 argues that the author used the Sententiae of Isidore. In consequence, we can say that also the De viris illustribus is earlier than 617.

 

There are two redactions of the work: the short one which consists of 33 chapters, and the long one of 46 chapters preceded with the preface (for the detailed differences see Codoner Merino 1964: 20-41). There is a discussion on the authorship of the long version, some scholars accept Isidorian authorship, other refute it. See Codoñer Merino 1964: 20-41. Codoñer Merino having studied in detail the manuscript tradition of both versions, opted for non-Isidorian authorship of the long version but still tentatively located its composition in the 7th-century Spain.