The "rest of Christianity" does not have an agreed canon.
Only the Catholic Church has voted on the Canon, which happened at the Council of Trent (15th century or thereabouts).
Early Christian codices included writings such as "Barnabas" and "The Shepherd of Hermas" as authoritative.
If the OT apocrypha are unacceptable, why did the NT writers quote them so heavily, such 1 Enoch and Sirach?
There is a number of very good scholarly books on canonization, and I can recommend some if you are interested.
Criteria employed by the Church Fathers for determining a writing as Scripture were: (1) Apostolicity (2) Orthodoxy (3) Antiquity (4) Use (5) Adaptability (6) Inspiration. ("The Biblical Canon", pages 401-42, Lee Martin McDonald)
As you can see from this list, the writings were accepted if they agreed with doctrines the church had already determined. The decision was thus determined by use, not imposed from the hierarchy
Doug