The Lists Came Early

If the canon had been imposed by a fourth-century council, we would expect no lists before it. We have them.
The Muratorian Fragment dates to roughly 170 to 200. It names nearly the whole New Testament - everything we hold except Hebrews, James, 1 and 2 Peter and 3 John - and it also names books it rejects. That is a community already sorting, already deciding, a century and a half before Nicea.
The first list matching our 27 exactly comes in 367, in Athanasius' Easter letter.
Note the shape of that. Not a sudden decree, but a long convergence: books read in worship, copied for other churches, quoted by teachers, and gradually recognised. Irenaeus quotes almost the whole New Testament as authoritative without ever publishing a list.
Scripture links:
- 2 Peter 3:15-16 - "as he does in all his letters... the other Scriptures."
- Luke 1:1-4 - "that you may have certainty concerning the things you have been taught."
- John 21:24 - "we know that his testimony is true."
Recognition took time. It did not take an emperor.