The Catholic Church added quite a good bit to the original writings, trust me Easter isn’t in the original writings by the disciples. Trinity isn’t in the Bible either, but that doesn’t stop 99% of the churches in this world from preaching it. The world of what people consider Christianity isn’t what the Bible really teaches.
I studied theology for a few years...I'm pretty well versed on this stuff. And it's debatable, high f'n debatable, that any writings were ever done by the so called disciples....because it's highly debatable that Jesus even existed in the first place. In some versions of the gospels Jesus isn't the son of the god and Mary wasn't a virgin. In some old books, not held canon by the church, Jesus wasn't a messiah but only a well educated teacher of the faith. The bible is a confusing hodgepodge of crap....and if you really want to make it even more confusing look into all the books that were considered by never included as canon.
I went through a phase in my life where religion really interested me. My parents believed in god but didn't support the church for a number of reasons and they raised us to question, study, learn, and think for ourselves. I got really into learning about everything from mainstream religions to the occult, spiritualism, and so much more. At the same time I became interested in physics and the science behind discovering the world around us. I didn't walk into it an atheist....but after years of reading and researching that's where I ended up.