Jerome, listing the writers of the church, says the Shepherd was written by the Hermas whom Paul greets in Romans 16:14 — which would make its author a contemporary of the apostles and put the book in the first century. The Muratorian Fragment, which is older than Jerome and closer to Rome, says the opposite: that Hermas wrote it quite lately in our times, while his brother Pius sat in the chair of the city, that is around 140 to 155. This dataset follows the Fragment, because a Roman list of what may be read in Roman churches is the better witness to a Roman book, and because the Shepherd's picture of a church with a settled clergy and a long memory of persecution does not fit the 50s. The confusion did not stop there. The traditional lists of the Seventy carry two more men of the name — Hermas of Dalmatia and Hermas of Philippopolis — neither of whom has a Wikidata item, so neither can be joined to this page by an identity row even to say they are different. They are named here instead. Four Hermases, then, and one book: the greeting in Romans, the two bishops of the Seventy, and the freedman who saw the tower being built.
De Viris Illustribus · DVI 10; Muratorian Fragment lines 73-80