The Didache—formally "The Teaching of the Twelve Apostles"—is a sixteen chapter handbook composed in Koine Greek around 90–150 AD, most likely in Syria or Asia Minor. Throughout, it emphasizes orderly community life, describing how to recognize and receive itinerant prophets, how to appoint bishops and deacons, and how to maintain hospitality and discipline within the fellowship. The work closes with a sober eschatological charge, urging believers to watch and pray for Christ's imminent return.

Although it was widely referenced by church fathers, the Didache itself was lost after the early centuries of Christianity and survived only in fragmentary quotations. In 1873, Greek Orthodox bishop Philotheos Bryennios discovered an eleventh century Greek manuscript (Codex Hierosolymitanus 54) in the library of the Jerusalem monastery of the Holy Sepulchre and published the full text in 1883. Since then, two much earlier papyrus fragments—one Greek from Oxyrhynchus and one in Coptic held by the British Museum—have confirmed its antiquity and helped scholars restore its original wording.