Countless men were burned, hung, martyred for the name of Christ Jesus, and these men were either contemporaneous to Jesus (had time to investigate the lie), or within the very early centuries after his death, and centuries after. Both the Gregorian and Julian calendar systems were based on his birth. He is mentioned in extra-Biblical literature, by those who lived in his era. Jesus is not a fictional name, it means Joshua in Hebrew, and others had forms of his name 'Bar-Jesus' or 'Jesus Barabbas'.
He didn't write anything, but what he spoke had so much impact that at least 8 other men wrote about him, and their works were copied by the tens of thousands, in multiple languages, in various geographical locations.
By the 3rd century AD, countless Christians were persecuted and tortured to death, and the movement never relented but grew to be one of the largest religions in the world. Millions of dollars, and millions of lives invested in the growth and sustainment of Jesus' legacy.
It would be much harder to substantiate how such a fallacy persisted at such a rate and intensity, than to concede his historicity.