I don't think he ever existed. All religions stem from mythmaking and Christianity is not an exception. People wanted to believe someone will save them while the Roman world they knew was crumbling all around them, destroyed by civil wars, foreign invasions, famines and epidemics. Christianity was a good cope for slaves, urban poor and the huddled masses of the Late Roman Empire. You're dirt poor in life? Don't worry little buddy you will get your reward in the afterlife. After all, it's easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God. You don't have Roman citizenship? No worries. My kingdom is not of this world. You feel like an outcast among strangers? Downtrodden and misunderstood? Think about it this way; there is neither Jew nor Greek, there is neither slave nor free, there is no male and female, for you are all one in Christ Jesus. After the religion got going, the Roman elites used it to try to hold together their multicultural Empire heavily divided on ethnic lines. They tried before with the cult of Sol Invictus but it didn't work out that well.