Hi John,
The sect of Christianity was basically started by Paul and Barnabus, before them, all believers in Jesus as the risen God were Jews,
As you can imagine, that caused a few rifts, to put it mildly, These early Jewish Christians, and that includes converts, had to obey all the Jewish laws, Kosha eating etc, and because of this, not too many people converted, so Paul said it was Gods wish that believers could eat whatever they wanted, coupled with the fact that Jesus was also called Christ, you have the beginnings of Christianity.
As an aside to this, its believed by some, that Jesus, whilst alive, belonged to a Jewish sect called the Essnes, which again, some think was the forerunner of Christianity.