The 39th Festal Letter of Athanasius (367 CE)
... Continuing, I must without hesitation mention the scriptures of the New Testament; they are the following: the four Gospels according to Matthew, Mark, Luke, and John, after them the Acts of the Apostles and the seven so-called catholic epistles of the apostles -- namely, one of James, two of Peter, then three of John and after these one of Jude. In addition there are fourteen epistles of the apostle Paul written in the following order: the first to the Romans, then two to the Corinthians and then after these the one to the Galatians, following it the one to the Ephesians, thereafter the one to the Philippians and the one to the Colossians and two to the Thessalonians and the epistle to the Hebrews and then immediately two to Timothy , one to Titus and lastly the one to Philemon. Yet further the Revelation of John
These are the springs of salvation, in order that he who is thirsty may fully refresh himself with the words contained in them. In them alone is the doctrine of piety proclaimed. Let no one add anything to them or take anything away from them...
But for the sake of greater accuracy I add, being constrained to write, that there are also other books besides these, which have not indeed been put in the canon, but have been appointed by the Fathers as reading-matter for those who have just come forward and which to be instructed in the doctrine of piety: the Wisdom of Solomon, the Wisdom of Sirach, Esther, Judith, Tobias, the so-called Teaching [Didache] of the Apostles, and the Shepherd. And although, beloved, the former are in the canon and the latter serve as reading matter, yet mention is nowhere made of the apocrypha; rather they are a fabrication of the heretics, who write them down when it pleases them and generously assign to them an early date of composition in order that they may be able to draw upon them as supposedly ancient writings and have in them occasion to deceive the guileless.
The canon was well established prior to the council that catholics suppose established the canon. Athanasius' list was known well before 367.
A good link for NT canon development is
http://www.ntcanon.org/
Actually to be precise it was Marcion in 146 AD — only we reject his canon which tossed out the OT completely