Dating the didache
The Didache, as it's called, chronicles a debate between the first Christians: do you have to be a Jew to convert to Christianity?
It is almost exclusively comprised of “practical” teachings, leaving aside any discussion concerning the dogmatic contents of faith, except in Chapter 16.
There are very few quotations from the Old Testament to be found in the Didaché; instead, the author speaks of the “Gospel of the Lord” (without specifying which of the Synoptics he or she might be referring to), and quotes and alludes to around twenty sayings or statements of Jesus Christ: ten of them literally, and others in paraphrase. In addition to authorship and dating, the treatise’s relationship with other Christian writings, such as the Gospel of Matthew and the Epistle of Barnabas, and even with Jewish prayers like the Kiddush, the Amidah, or the so called “manual of discipline” of the Essene community at Qumran, have all been the subject of study.
The Didaché, a brief, anonymous Christian treatise, was written between the years 65 and 80 (according to most scholars) and held in the highest esteem by the early Church Fathers.
After the text was lost for years, the Metropolitan of Istanbul, Philoteos Bryennios found a Greek copy in 1873 and published it in 1883. The main value of this treatise is that it provides us with extra-biblical data regarding the institutions and life of the earliest Christian communities.The Didaché codifies the rules and moral, liturgical and legal dispositions of the early Church that were considered to be convenient and necessary at the time it was written.It is considered the first and oldest written catechism, and as such has been respected and preserved to this day.Both the author and the place where the Didaché was written remain unknown.If you want to read the Didaché, here’s a full version of it, in English.
A specifically Christian document pre-dating the New Testament has been found.