that's a good question, and here is your answer. The earliest Christian communities, remote from power and lacking in wealth, were led by charismatic agitators, peripatetic "prophets" and "teachers" who claimed their doom-laden message was received directly from the Holy Spirit of God. Their doctrine was spontaneous, variable and idiosyncratic.

Tellingly, the handful of late 1st century and early 2nd century writers (Paul, Clement, Barnabas, Papias) did not quote the mythical Jesus at all. They say nothing, or next to nothing, of humanoid "Jesus actions" or miracles. The virgin-born, miracle-working, godman of later legend was unknown to them. When their fantasy required the endorsement of higher authority they turned instead to Jewish scripture, to the patriarchs, the prophets and the supposed utterances of the Jewish God himself.

There are some scriptures that claim Jesus lived and was persecuted a century before the time period, and others that claim other dates. It is clear that there were many local myths and god-man legends (Persian, jewish, Egyptian, and Greek) that were combined in the person of Jesus later by the authors of the Gospels.

They weren't crazy (at least some of them werent. The dude who wrote the "revelation" was certainly insane. They were preaching against Rome and persecution of their people and homeland by metaphor and analogy.