Jesus was a legitimate historical figure. There are a number of accounts of people contemporary to him who knew him personally. Some of the overarching details of his life are uncertain, but 2 things are mostly universally agreed upon as historical fact.

1. He was baptized by John the Baptist.
2. He was crucified in or around Jerusalem during the Governorship of Pontius Pilate.

Those two things are the only things about him that hold a high degree of certainty as historical fact. Everything else is subject to a fair degree of skepticism.