This combined work of Jerome and Gennadius is unique and indispensable in the history of early Christian literature, giving as it does a chronological history in biographies of ecclesiastical literature to about the end of the fifth century. For the period after the end of Eusebius Church History it is of prime value.
1. The work of Jerome was written at Bethlehem in 492. It contains 135 writers from Peter up to that date. In his preface Jerome limits the scope of his work to those who have written on Holy Scriptures, but in carrying out his plans he includes all who have written on theological topics; whether Orthodox or Heretic, Greek, Latin, Syriac, and even Jews and Heathen (Josephus, Philo, Seneca). The Syriac writers mentioned are however few. Gennadius apologizes for the scanty representation which they have in Jerome on the ground that the latter did not understand Syriac, and only knew of such as had been translated.
The motive of the work was, as the preface declares, to show the heretics how many and how excellent writers there were among the Christians. The direct occasion of the undertaking was the urgency of his friend Dexter, and his models were first of all Suetonius, and then various Greek and Latin biographical works including the Brutus of Cicero.
Jerome expressly states in his preface that he had no predecessor in his work, but very properly acknowledges his indebtedness to the Church History of Eusebius, from whom he takes much verbatim. The first part of the work is taken almost entirely from Eusebius.
The whole work gives evidence of hasty construction (e.g., in failure to enumerate the works of well-known writers or in giving only selections from the list of their writings) but too much has been made of this, for in such work absolute exhaustiveness is all but impossible, and in the circumstances of those days, such a list of writers and their works is really remarkable. He apologizes in the preface for omitting such as are not known to him in his “Out of the way corner of the earth.” He has been accused of too great credulity, in accepting e.g., the letters of Paul to Seneca as genuine, but on the other hand he often shows himself both cautious (Hilary, Song of S.) and critical (Minutius Felix De Fato).
The work was composed with a practical purpose rather than a scientific one and kept in general well within that purpose—giving brief information about writers not generally known. This is perhaps why in writings of the better known writers like Cyprian he does not enumerate their works.
2. The work of Gennadius was written about 430 according to some, or 492 to 495 according to others. Ebert with the Benedictins and others before him, makes an almost conclusive argument in favor of the earlier date on the ground that Gennadius speaks of p. 354 Timotheus Aelurus who died in 477 as still living. This compels the rejection of the paragraph on Gennadius himself as by a later hand but this should probably be done at any rate, on other grounds. The mss. suggest that Gennadius ended with John of Antioch, although an hypothesis of three editions before the year 500, of which perhaps two were by Gennadius, has grounds. The bulk of the work at least was composed about 480 (probably chapters 1–90) and the remainder added perhaps within a few years by Gennadius or more probably two other hands.
Gennadius style is as bare and more irregular than Jeromes but he more frequently expresses a critical judgment and gives more interesting glimpses of his own—the semi-Pelagian—point of view. The work appears more original than Jeromes and as a whole hardly less valuable, though the period he covers is so much shorter.