Or the Gospel authors exaggerated the witnesses and events or fabricated everything.
1) Can you prove that
2) If they had fabricated everything they would have been very easy to dispute.
1) You're unclear on where the burden of proof belongs here.
2) There's no contemporary historical evidence of Jesus' existence. It's really not that hard to dispute.
Actually the evidence is quite ubiqoutus, you just need to study. Most historians accept that Jesus was a real person just like most accept that Buddha and Muhammad were real people. Supernatural occurances happened in their lives, why is Jesus excluded as a real person?
The burden of proof belongs on the atheist in this case since you would have to somehow prove thay were so dishonest and that they'd even go to their deaths for it (people do senseless things but not this senseless). The fact is that we know that Pontius Pilate, Ananaeus, (or Ananias), Paul, Peter, Mary, Elizebeth, John, Luke all existed and the apostles themselves were eye witnesses.
To find conformation for what I have said follow this link
www.AlwaysbeReady.com if you havn't been there before. If you have then you probably already know.
The evidence is overwhelming, study a bit. Jesus did exist.