This is why independent manuscripts and archaeological evidence is needed just to try and fill the gaps. Imagine a future historian trying to write a history of the post-Civil War American Frontier if all he had available was a few TV horse operas and Hollywood westerns.

Jesus certainly did exist, and the major recorded details of his life are probably correct. I doubt it would have been possible for the legend to have survived if he were a totally fictitious figure. But as RL points out, the miracles were hogwash.

The best explanation that fills the facts is that he was a charismatic political/religious leader who had a brief but extensive ministry that left a lasting impression among a corps of loyal followers who spread his ideas across the Hellenistic world. He was executed by the Roman authorities in order to mollify Jesus’ own Jewish rivals. That pretty much matches up with the Biblical account.

Here is the disputed, and possibly altered, testimony.

Testimonium Flavianum
About this time there lived Jesus, a wise man, if indeed one ought to call him a man. For he was one who performed surprising deeds and was a teacher of such people as accept the truth gladly. He won over many Jews and many of the Greeks. He was the Christ. And when, upon the accusation of the principal men among us, Pilate had condemned him to a cross, those who had first come to love him did not cease. He appeared to them spending a third day restored to life, for the prophets of God had foretold these things and a thousand other marvels about him. And the tribe of the Christians, so called after him, has still to this day not disappeared.

Flavius Josephus: Antiquities of the Jews, Book 18, Chapter 3

“Jesus, why’d you pick such a backward time and nation?
Israel in 4 BC had no mass communication.”

–Judas’ song
“Jesus Christ, Superstar”

The parallels of the Jesus story with that of Zoroastrianism and other early middle eastern religions is striking. Zoroaster and others walked on water, fed the poor, healed the sick, rose from the dead, etc. Early christianity can be considered the Middle East’s greatest hits. It is for this reason a significant number of historians question whether Jesus ever actually exists.

My personal belief is someone named Jesus existed and was crucified, but he was probably a madman who heard voices and his story was picked up on and embellished a couple centuries later by the writers of the New Testament.