What we believe happened in historical times changes all the time, often quite significantly. You may not be aware of it, but that is not important.
And what do you think on the Christ question. Do you think there is enough evidence to conclude that individual was crucified.
And yes, religion goes change all the time. Our understanding of the bible evolves all the time as well, as we have a better grasp on ancient languages and archeology, as well as the discovery of more copies of biblical texts. Why do you think every one got so excited when the Dead Sea Scrolls were discovered or with the recent discoveries of the gospel of Thomas?