It appears that certain of the four gospels now considered canonical were once disputed, but Irenaeus insisted that there be four gospels, just as there are four corners of the earth.
Bishop Eusebius of Caesaria, a leading church historian and contemporary of Constantine in the fourth century, wrote the Storia Ecclesiastica, in which he provided the first complete surviving list of what the Christian Bible should contain. He wrote:
It will be well, at this point, to classify the New Testament writings. We must, of course, put first the holy quartet of the Gospels, followed by the Acts of the Apostles. The next place in the list goes to Paul’s Epistles, and after them we must recognise the Epistle called 1 John, likewise 1 Peter. To these may be added, if thought proper, the Revelation of John …. These are classed as Recognised Books. Those that are disputed, yet familiar to most, include the Epistles known as James, Jude, and 2 Peter, and those called 2 and 3 John, either the work of the evangelist or of someone else with the same name.
Eusebius said of Revelation:
As for the Revelation of John, if this seems the right place for it: as I said before, some reject it, some include it among the Recognised Books and so it has remained, but not without argument!
At the time of the Reformation, the canon of the Bible was called into question. Martin Luther condemned the Epistle of James as worthless, and similarly denigrated Jude, Hebrews and Revelation.
Wikipedia lists the seven New Testament books regarded by the Catholic Church as deuterocanonical because they were not universally accepted by the early Church:
- The Epistle to the Hebrews
- The Epistle of James
- The Second Epistle of Peter
- The Second Epistle of John
- The Third Epistle of John
- The Epistle of Jude
- The Apocalypse of John (also known as the Book of Revelation)