The Didache, also called The Teaching (or Doctrine) of the Twelve Apostles, is a short treatise that dates back to the early Christian Church and was accounted by some of the Fathers as next to Holy Scripture.
The Didache was discovered in 1873 by Philotheos Bryennios, Metropolitan of Nicomedia, in a small eleventh century codex of 120 pages. He astonished the world by publishing a text towards the end of 1883.
The Didache falls into two parts:
The first part (Chapters 1-6) is a moral treatise describing the Two Ways, the Way of Life and the Way of Death. The second and third parts contain instructions on baptism, the Eucharist, fasting, prayer, matters of church organization, apostles and teachers, prophets, bishops, and deacons. The Didache is perhaps the first text to append a doxology to the Lord's Prayer: "...for thine is the power and the glory unto all ages."
Egypt and Syria both have claims as the place of origin for this text. The case for Egypt was put forward because Clement of Alexandria is an early witness to it and it was also very popular in Egypt, in the fourth century, based on Athanasius the Great's reference to it and the numerous Coptic and Ethiopian versions available. The case for Syria lends itself to links in the text on ministry and the reminiscence of the apostolic decree of Acts xv, 23-9; characteristic of early Syrian Christianity. The text in chapter 6 seems to have envisaged a largely rural community which also tends to point to Syria rather than Egypt.
The edition of The Didache in Sources Chretiennes, by W. Rordorf and A. Tuilier (no. 248, Paris, 1978) has a good bibliography as well as excellent introduction and notes for this piece of work.