Atheists often argue that there is no historical evidence outside of the Gospels that Jesus Christ ever existed. However, at least one atheist is honest enough to admit in this two-part article that history does confirm that Jesus Christ did live in first century Israel:
An Atheist Historian Examines the Evidence for Jesus (Part 1)
An Atheist Historian Examines the Evidence for Jesus (Part 2)
Since he is an atheist, the author does not accept the Gospel accounts as completely historical and tries to interpret them from a naturalistic viewpoint. However, he does show that the Gospel accounts make sense only if Jesus actually existed and was not made up by early Christian believers. He also shows that there is more non-Christian testimonies that Jesus existed than there is for some other historical figures. I hope these articles prove useful to you.