Their writings, like those of the apostles, are epistolary; but editions of the apostolic fathers now usually admit also the early Church order known as the Didache, the allegory entitled the Shepherd, and a short anonymous apology addressed to one Diognetus.
It died out very gradually, and the Didache or Teaching of the Apostles, compiled probably between A.D.
The Didache and Justin Martyr are no less unsatisfactory from the Roman point of view.
Here it is followed by the Shepherd of Hernias, while in an 11th-century MS., which contains also the Didache, it is followed by two writings which themselves form an appendix to the New Testament in the Codex Alexandrinus.
Besides The Didache and the Epistles of Clement it contains several spurious Ignatian epistles.