The Biblical canon is the set of books Christians regard as divinely inspired and thus constituting the Christian Bible. Though the Early Church used the Old Testament according to the canon of the Septuagint (LXX), the apostles did not otherwise leave a defined set of new scriptures; instead the New Testament developed over time.
The writings attributed to the apostles circulated amongst the earliest Christian communities. The Pauline epistles were circulating in collected form by the end of the first century AD. Justin Martyr, in the early second century, mentions the “memoirs of the apostles,” which Christians called “gospels” and which were regarded as on par with the Old Testament.[3] A four gospel canon (the Tetramorph) was in place by the time of Irenaeus, c. 160, who refers to it directly.[4] By the early 200’s, Origen may have been using the same 27 books as in the modern New Testament, though there were still disputes over the canonicity of Hebrews, James, II Peter, II and III John, and Revelation (see also Antilegomena).5] Likewise by 200 the Muratorian fragment shows that there existed a set of Christian writings somewhat similar to what is now the New Testament, which included the four gospels and argued against objections to them.[6] Thus,** while there was a good measure of debate in the Early Church over the New Testament canon, the major writings were accepted by almost all Christians by the middle of the second century.**7]
In his Easter letter of 367, Athanasius, Bishop of Alexandria, gave a list of exactly the same books as what would become the New Testament canon,[8] and** he used the word “canonized” (kanonizomena) in regards to them**.[9] The African Synod of Hippo, in 393, approved the New Testament, as it stands today, together with the Septuagint books, a decision that was repeated by Councils of Carthage in 397 and 419. These councils were under the authority of St. Augustine, who regarded the canon as already closed.[10] Pope Damasus I’s Council of Rome in 382,** if the Decretum Gelasianum is correctly associated with it, issued a biblical canon identical to that mentioned above**,[11] or if not the list is at least a sixth century compilation.[12] Likewise, Damasus’s commissioning of the Latin Vulgate edition of the Bible, c. 383, was instrumental in the fixation of the canon in the West.[13] In 405, Pope Innocent I sent a list of the sacred books to a Gallic bishop, Exsuperius of Toulouse. When these bishops and councils spoke on the matter, however, they were not defining something new, but instead “were ratifying what had already become the mind of the Church.”[14] Thus, from the fourth century, there existed unanimity in the West concerning the New Testament canon (as it is today),[15] and by the fifth century the East, with a few exceptions, had come to accept the Book of Revelation and thus had come into harmony on the matter of the canon.
Conclusion: With all these Church Council decided which Books in the Bible are inspired and canonical, it was the Catholic Church who form the Bible both OT and NT. This was way before the 1054 AD Schism between the East-West, and before the Protestant Reformation in 1500s. There was One Church then and it was Catholic. The Catholic Church gave you the Bible.
