Tacitus’s mentioning “Christus”

[Jenny A]

I don't believe the cuxifiction was the only event that started Christianity.  Paul's evangelism the disciples' evangelism, Jesus' preaching,  jewish history,  and many other things were involved in the creation of Christianity. 

Let me ask you this do you believe that there was a Joseph Smith?   Was he lynched?

I said started, (originated, or began) with the notion that Jesus Christ existed.
I have yet to confirm IF he existed, you are already there.

Have you any reason to believe Jesus did any of the things you mentioned?
If you are referencing the bible, are you aware of the many contradictions in it? Therefore not making the bible a reliable source.

Since you state that it wasn't merely Jesus Christ existence that started Christianity, you are making extreme claims.
At this stage I don't actually feel jesus preached anything at all. On the contrary, I feel the LACK of evidence point only to the possibility a Christus (or whatever the strange name) existed NOT that he also preached! That would be taking things to the extreme!

Now you are being silly.  If he did not preach, why would anyone remember him at all. He wasn't the only jew crucified.   
The gospels and Paul's letters are good evidence he lived and preached.  They were however written too long after his death and by sources much too biased to be considered good evidence of the details.  Some parts of them such as the birth story are obviously false. Other parts unverifiable.