This is not an easy question to answer. Whenever we talk about the rise or beginnings, especially when the topic in view is old, there is much uncertainly and debate. With that said, we can firmly say a few things.
First, there are three branches of Christianity. The Orthodox church, the Catholic church, and the Protestant church. All three branches claim to be original and faithful to the teachings that emerge from the Bible.
Second, the Bible - the Old and New Testaments are foundational. Christianity is a religion based on a texts. Even if modern churches have veered from a firm belief in the Bible, they have been shaped in their history.
Third, a reading of the pastoral epistles - 1 Timothy and Titus, and the book of Acts offers some hierarchy. The picture is not clear. This is why the church today has three forms of government, roughly speaking: the bishop model, the presbyterian model, and the congregational model.
Fourth, as to the spread of Christianity, it was largely due to missionary endeavors. Also the importance of Constantine, the Roman Emperor should be emphasized.
Fifth, When we look at the church in view of modernity, we can say that as much as the church influences the world, the world also influences the church. This give and take is inevitable.