This paragraph of mine in the comments:
Irenaeus may have had good theology, but that's because he also was among the first to have an almost totally compiled New Testament. It wasn't "the Catholic Church" that put it together. Paul's works were most likely collected in his own lifetime. The Gospels and other letters were also collected in a group -- but there was no doubt they were regarded as Scripture from the moment the ink was dry.
Got some comments of its own. One commenter wrote:
your last paragraph is utterly unsupported dogmatic affirmation--essentially a form of sanctified wishful thinking. … You're right that the NT was _mostly_ canonized in the second century, as far as we can tell. But clearly it _was_ the early "Catholic Church" (i.e., the group of Christians from whom all modern Christians are in one way or another descended) that put it together. Your claim that Paul's letters and the Gospels were compiled and accepted as Scripture almost as soon as they were written makes no sense if Irenaeus was the first person to be working with an "almost completed canon." That's 100 years later. I have trouble seeing how you aren't contradicting yourself here.
It is the very nature of this "early 'Catholic Church'" that is in question. Yes, they saw themselves as one church. But don't give people the notion that this group of Christians had uniform worship or organizational structures. In fact, that is the very thing that is in question.
1 Clement, written from Rome eastward (towards Corinth) reflects a different church government structure than does Ignatius (writing from the east westward). Easter was celebrated differently in the east (Quartodecimans) and in the west. They were by no means an organized body with an organized governmental or liturgical structures.
So who were "they", and by what mechanism did "they" "put it together"? Likely they had good communication among themselves, and a common purpose. But that can be said of the Southern Baptist Convention, and that in no way suggests organizational unity.
So who were "this group", and by what mechanism did "they" "put it together"? We have some evidence.
Paul wrote in the 50's and 60's. While they didn't have Kinko's there at the time, it's almost a sure bet that his letters were circulating as a unit as soon as Christians were able to regroup from persecutions. The Chester Beatty papyrus, dated 200, contains the complete set of Paul's letters.
The Gospels were written at different times and places. The Gospel of John is typically dated at around 90 AD. There is no question that these two sets of documents were compiled early and often. Stanley Porter says "there is surprisingly strong manuscript evidence worth considering that indicates that sometime in the second century the fixed corpus of four Gospels and Acts was firmly established" (How We Got the New Testament 87).
Tatian's Diatesseron, circa 150-180, is likely as early as they were all collected in one place. It is very likely that Irenaeus at least had all of these documents.
Porter also relates "Majescule Manuscript 0232", dated to the third century, which has compiled a Johanine corpus. No doubt these documents had been thought of as a unit and had been collected earlier (in order to create this compilation).
1 Peter, 2 Peter, and Jude were also compiled separately in an early codex.
Some date the Muratorian canon as early as 170; that contains virtually the whole NT canon.