After Irenaeus, Earle Cairns mentions the school of Alexandria.
These people loved Greek classics and tried to teach Christianity with them.
They developed the four interpretations of Scripture along with the grammatico-historical interpretation. To them the literal meaning corresponds with the body, "a hidden moral meaning" that corresponds to the human body, and and "underlying spiritual meaning" that the elite Christians can tap into, this hidden knowledge (Cairns 110). This has led to unscriptural interpretations of Scripture that were not remedied until the Reformers went back to only using grammatico-historical meaning.
Clement of Alexandria was a cool guy. He wrote "Shepherd of Tender Youth". It's the oldest hymn where we know who wrote it. He promoted Christianity by making it the "true Gnostic." The true search for knowledge.
Then, Origen succeeded his place. He had the most extensive writings that can be compared with Augustine. However, these four interpretations of Scripture led him to heresies such as Arianism (Jesus being subordinate to God), universalism, and the denial of a physical resurrection. A denial of every defining characteristic of Christianity.
This is why we must study the Bible within it's historical and grammatical context. Not just read it literally, but also not to insert allegories that don't belong there. Read each genre like it is. This was the first real Emergent Church. I can't judge the salvation of these people, but if anyone tells you that there is secret Bible knowledge that only certain people can access, run the other way. God wrote nothing in secret and has revealed everything we need to know in Scripture.