Luke testifies that his eyewitness informants who saw Jesus “from the beginning” were also Christendom’s direct teachers (* Luke 1:1-4 — “[The stories of Jesus were] handed down to us by those who from the beginning were eyewitnesses and servants of the word...”).1
A full page will discuss these arguments
This is relevant because it is prima facie unlikely to be a lie,4 and teachers/performers of oral tradition by their very nature are the primary disseminators of trusted information. They held captive audiences who felt the given teacher was well-known and vetted, and so they were disposed to trust the teacher. (And, relevantly, oral teachers/performers in general felt proud and obligated to share their story with gusto.)
The apostles would habitually teach, traveling Palestine—and later the mediterranean—to do so. In the process they would found, check on, and strengthen churches.
This page analyzes 11 kinds of evidence:
This is relevant because, if the apostles were often checking up on churches, teaching, and event starting them, then we can anticipate that their witness-based testimony was constantly circulating among Christendom.
The Jerusalem church pass-down Jesus-bio (delivering to their successors and even other churches).
A full page will analyze these arguments:
This is relevant because the Jerusalem church--which included the apostles and many witnesses from the area--would have being a true hub of eyewitness testimony.
But so what?
Whether or not it predominated over legend (a seperate question) in the AD 30-70 Mediterranean, witness-based testimony on Jesus’s life and ministry truly thrived.
This page analyzes 10 arguments:
This is relevant because if the witnesses were actively teaching the churches, then of course witness-based Jesus-biography would thrive.
AD 30-70 Christians orally inherited and passed down (i.e. popularized) storied reports about Jesus’s ministry.
A page at /early-christians/pass-down/jesus-biography will analyze 7 arguments:
This is relevant because for each passing down, the amount known Jesus-bio would increase (and so thrive).
But so what?
The Gospel of Luke opens up with a note informing readers that, in fact, many written biographies of Jesus had already been circulated.
This is relevant because it is unlikely to be a baldfaced lie (there was not even a motive for this); his own patron—Theophilus—would likely know better. And if others had put together complications of the Jesus stories, then it seems true indeed that such stories were circulating and circulating well.