I'm coming in here very late, and have not read every comment.
My understanding, from those who have tackled the subject with some objectivity, is that there is a probability of a historical figure, maybe named
Yeshua, who had a brother James, and they were political radicals of their day.
The Gospels were written sometime in the 2nd Century AD, as first hand accounts. Historical Roman records of the time, in the hands of monks, were
edited and retrofitted to conform to their interpretations. Stylist analysis demonstrates the writing of Josephus have later insertions acknowledging
Yeshua as venerated in his time.
The historical Yeshua was likely crucified for dissidence, the standard form of Roman execution. The structure on which this was done was more
T-shaped and not a cross, by the way.
For many in the late days of the Roman Empire, an increasingly influential mystical Gnosticism evolved towards what would eventually become
Christianity. A longstanding Greek concept of "Christos" or saviour, was imposed on the otherwise minor Judean provincial historical figure,
imbuing him with mythical qualities and elevating his role to a Son of God sent to redirect mankind towards a religious understanding the early
proto-Christians were embracing.