Spot on, Alex!
From the Orthodox article:
The final acceptance of exactly this set of 27 books by everyone except the Nestorians (who accept five fewer) and the Ethiopians (who accept more) took some time particularly for Hebrews (because the Roman church was unsure of its authorship), Revelations (because it was easily misused by those with apocalyptic fantasies), and Jude (because it quoted from the apocryphal book of Enoch). While II Peter previously was the most disputed book,(53) by this point, it was less controversial to the Christian mainstream. For instance, St. Cyril of Jerusalem (c. 315-386) and St. Gregory Nazianzus (329-389) accepted all 27 books except Revelation. On the other hand, in 405, Pope Innocent I wrote a letter which affirms a 26 book canon that excluded Hebrews.(54) Clearly, it took some time to achieve universal acceptance among the Orthodox for Hebrews in the West, and Revelation in the East.
The Western Council of Hippo (393) was probably the first council to specify the limits of the canon, and it accepted the 27 book canon, allowing only them to be read in church under the name of canonical writings. It “permitted, however, that the passions of martyrs, be read when their [martyrdoms’] anniversaries are celebrated.”(55)
Some accepted larger canons as well. St. Epiphanius of Salamis (c. 315-415) accepted all 27 books but also accepted the Wisdom books of Solomon and Ben Sirach. The late fourth century Codex Sinaiticus included Barnabas and the Shepherd “at the end but with no indication of secondary status.” The early fifth century Codex Alexandrinus made “no demarcation between I and II Clement” and the rest of the New Testament. St. Jerome (c. 342-420), the translator of the Vulgate and one of the greatest scholars of the early church, seemed to believe that Barnabas and the Shepherd were worthy of inclusion. However, he recognized that they were not in the accepted canon, and he did not believe that anyone had the authority to add them. He also noted that many still rejected Jude because of its quotation from Enoch.(56)
The canon of the Syriac-speaking churches in the third century included the Diatessaron and the fourteen Pauline epistles. In the early fifth century, the Peshitta became the official text of Syriac-speaking churches. It replaced the Diatessaron with the four gospels. It contained the 22 books of our New Testament other than II Peter, II John, III John, Jude, and Revelation. (The Peshitta is traditionally held to be the work of Rabulla, bishop of Edessa from 412-435. However, it probably built on work of the previous century.) The Nestorian church still uses this 22 book canon. In 508, the Jacobite branch of the Syriac church came to accept the standard 27 book canon.(57)
The longest Biblical canon belongs to the Ethiopian church. Their Old Testament contains the Septuagintal books, Jubilees, the Ethiopic Enoch, IV Edras, the Rest of the Words of Baruch, the Ascension of Isaiah, and other books. Their New Testament includes the Shepherd and other books. Some manuscripts of the Ethiopian New Testament include the Epistle of Eusebius to Carpianus and the Eusebian Canons which were written by Eusebius, bishop of Caesarea (c. 260-c. 340).(58)
I had deleted it to save space, but the full article is worth reading. Please remember that “the Church” doesn’t mean the Catholic Church to anyone except Catholics.
There has also been a dispute in the Catholic Church about what canonical means - are all ‘scriptures’ of equal value, or are some not useful for determining doctrine. I get in over my head on this discussion - I believe the Council of Trent left that as an open question.