Not much changed with Christianity with the advent of the Roman Empire at first. They had the same practices, similar beliefs, and a consistent way of life. To be sure, at times it was difficult due to persecutions. There were several persecutions under Nero, Domitian, and Decius. But even during these times, the persecution was not so great that it altered Christianity all that much.
What did change Christianity a decent amount was something unlikely and surprising. When Christianity gained the favor the Roman Empire under Constantine, things began to change slowly. Christianity, instead of being a small religion, started to gain in power. They started building larger churches and their power grew. We can say that Christianity became more worldly.
Many things have stayed the same just the practices did not it changed over time. The basis of catholiscism & modern day christianity like protestantism is that we believe christ was crucified and risen the third day and he atoned for all of our sins. All types of christianity believe in this idea. Catholiscism is actually not really the first type of christianity the first christians where in fact jews lead by st.peter and his many followers as the legend goes Constantine was once a persecutuer like St.paul also called saul of tarsus, but constantine had a vision of a cross in the sun which he ordered that everyone of his soldiers to put a cross on there shields for battle with thier enemies basically the roman empire or paganism for that matter.
I know that constantine was a master at warfare and wasn't ignorant and in fact was very intelligent and very modest and decent looking. Constantine was said, to have three great cities conquered Alexandria, Egypt which brought forth the coptic church he conquered what is modern day istanbul,turkey which he called constantinople and he conquered the roman empire. His teachings where that where in what took place at "the council of nicea" in which the books of the bible where chosen, yet their where more books than the gospels we have today in fact know one of the early church father's included some if many Judeao-christian books like: the book of enoch, apocalypse of st.peter, the other letters of paul and much more indeed...
Even the church did not consider these books heretical, but they where just written 300 years after the crucifixion which was in fact the deadline for them to be put in the bible yet some where considered way to hard to believe. The church archives do contain hidden books and the catholic church surprisingly still reads them. Mainly highly religious officials, but still reads them. Today the church still has it's touch and in fact has been the same even after "the reformation" it's just their views have changed. Many scholars believed that Jesus never could have died on the cross and would be given to a wealthy, yet secret disciple of Jesus known as Joseph of Arimethea because the romans would have just let Jesus stay upon the cross and let the elements do the rest.
Archaeology is almost like the gospels best friend because they have found ossuarys bone boxes which the person had still a wooden steak in his foot yet that persons burial was very somewhat sacred because it was in a tomb. So the gospel account of Jesus was possibly true and in fact he was given to a wealthy man to have a respected burial.
This was what I believe might have actually occured, but more scientific research is needed of this sudden possiblity. No church has changed in our world. Many say the gnostic writing known as the nag hammadi library where written before the gospels yet the oldest gospel of mark was written 70 years after the crucifixion and in fact is older than all of the gnostic writings which date to 500 ad. which is far to much out of date from Jesus' time frame.
So it matters how you view the bible their are no contradictions, but their are many mysteries more than answers.