Hermas, as the author of the well-known early treatise called The Shepherd, is usually reckoned one of the Apostolic Fathers (q.v.). The work is quoted as inspired by Irenæus and Clement of Alexandria. To the Montanist Tertullian it is 'that apocryphal Shepherd of the adulterers'; but Eusebius, while he places it in his list of spurious or rejected books, witnesses that it had been read publicly in the churches. And indeed the 'commandments' were read here and there in the Eastern Church from the 4th to the 15th century, though nowhere with the honour of Scripture. The date and the authorship are both in dispute. The suggestion first advanced by Origen, in the 3d century, that the Hermas mentioned in Romans might be the author, may be dismissed in company with the assertion of the Ethiopic scribe that Hermas was none other than St Paul. The statement of the writer of the Muratorian Fragment has been generally accepted, that Hermas was the brother of Pius I., Bishop of Rome about the middle of the 2d century, and that he wrote during his brother's episcopate; but the form of church government that appears in The Shepherd is against this tradition, as perhaps is also the jealousy the writer displays of those who are ecclesiastically his superiors; and moreover the treatise was already in general use considerably before the end of the century. From these and other considerations there has been in recent years a tendency to throw the date back to the beginning of the 2d century, and to identify a certain Clement who is mentioned with Clement (q.v.) of Rome. This last point is a mere assumption, but in favour of the earlier date is most of the internal evidence, as well as the fact that the book was read in public—an honour restricted in every other instance to writings accepted as those of the Apostles or their immediate disciples; against it are the allusions to the persecutions suffered by the Christians, the condition of the Roman Church, and the absence of all reference to Judaizing Christians. Finally, Donaldson's theory that the name Hermas is fictitious, and the whole work an allegory, appears to be based on a misconception. The treatise, which is divided into three parts—visions, commandments, and similitudes—contains little of positive dogmatic teaching, but is an interesting monument of early Christian thought; it was intended primarily to rebuke the worldliness that had come upon the church, and to turn sinners to repentance.
Latin translations were in use before the end of the 2d century, and for long the work was known only through a score of MS. copies of one of these versions. A second Latin version has been discovered, however, as well as an Ethiopic version, found by D'Abbadie in 1847, and edited by him with a Latin translation (Leip. 1860). Of the Greek text the Codex Sinaiticus supplies about one-fourth, to nearly the end of the fourth commandment; the rest, except about seven short chapters, is in the Athos MS. Considerable portions are found in Pseudo-Athanasius and Antiochus Palæstinensis, who have borrowed extensively from Hermas without acknowledgment. In 1890 the discovery of a new Greek codex, contemporary with the Sinaiticus, and containing the whole of Hermas, was announced. There is a 'complete' Greek text by Hilgenfeld (1888), who has also edited the Latin form (1873); and a Collation of the Athos Codex has been made by Dr Spyr. P. Lambros (trans. with preface, &c., by F. A. Robinson, Camb. 1888). There is a good edition of Latin and Greek by Gebhardt and Harnack (1877). See also Zahn, Der Hirt des Hermas (1868); Donaldson, The Apostolical Fathers (1874); Salmon's Introduction to the New Testament (4th ed. 1889); and Johns Hopkins University Circulars, iii. 75 and iv. 23.