RE: Chritianity Originated From Pagan & Jewish Mystery Religions
Christianity was started by the followers of Jesus Christ. This is just one example:
(1 Corinthians 15:3-8 NIV) For what I received I passed on to you as of first importance : that Christ died for our sins according to the Scriptures, {4} that he was buried, that he was raised on the third day according to the Scriptures, {5} and that he appeared to Peter, and then to the Twelve. {6} After that, he appeared to more than five hundred of the brothers at the same time, most of whom are still living, though some have fallen asleep. {7} Then he appeared to James, then to all the apostles, {8} and last of all he appeared to me also, as to one abnormally born.
The Apostle Peter testifies about Jesus as well,
(2 Peter 1:16 NIV) We did not follow cleverly invented stories when we told you about the power and coming of our Lord Jesus Christ, but we were eyewitnesses of his majesty.
As I mention in my post about Paul in which I wrote;