Literary (documentary) and archaeological evidence of Jesus
There is very good historical evidence outside of the Bible that Jesus lived. More than thirty extrabiblical sources mention Him within 150 years of His life. And they don’t just mention Him, they corroborate numerous details spoken about Him in the New Testament. http://www.alwaysbeready.com/extrabiblical-historical-sources-corroborate-the-bibleWe can learn quite a bit about Jesus from historians who were not Christian. http://www.biblicalarchaeology.org/daily/people-cultures-in-the-bible/jesus-historical-jesus/did-jesus-exist/
In addition to classical pagan sources chronicling the life of Jesus and His followers, there are also a number of ancient hostile Jewish sources describing Jesus. http://coldcasechristianity.com/2014/is-there-any-evidence-for-jesus-outside-the-bible/