Evidence For Jesus Outside The Bible

This is a side-note, as Muslims are unable to deny that Jesus existed, and the topic here is to demonstrate Christianity to Muslim audience.  Nevertheless, in case someone claims that Jesus never existed, I find this video convincing, along with the associated text form of the video:

https://www.youtube.com/watch?v=4bLlpiWh9-k (Is Jesus Real? - Non-biblical Evidence of His Existence)

http://thedevineevidence.com/jesus_history.html (TheDivineEvidence.com)

We sometimes view the Bible as a monolithic work, just because it is all between the same two cardboard covers.  Actually it is a collection of (mostly) independent works by different authors who did not always agree on everything.  It contains many historical references that are well-corroborated with secular history.  The authors of the New Testament clearly intended for their works to be treated as true, historically accurate accounts. 

Even without referencing non-Christian sources for the existence of Jesus, the critical question is this: If the New Testament is made-up fiction, how did the New Testament ever get a crowd of followers to read, and re-copy its manuscripts  and pass them down to the next generation all the way to us?  The New Testament is not boring, but it also does not fit the genre of "entertainment".