Christianity was generally a dormant force for the first three hundred years of its existence. Its rise actually occurred in early 4th Century C.E., when Constantine the Great made it the state religion by his own decree. Constantine had just returned from conquering the Ottoman Empire.
Constantine had conquered a vast territory with immense wealth, which was the reason of the initial invasion. He had defeated the Ottoman soldiers, nearly killing them all. But Roman soldiers also suffered many casualties. Thus, Constantine needed peace. Instead of continuing the public policy of persecution of his troublesome Christian sect, he made Christianity the "legal" religion. After commissioning, or commanding, that 50 copies of a New Testament of Jesus be written, he established the Roman Catholic Church within the Ottoman Empire.
This was, in fact, the beginning of the Holy Roman Empire. The Church became the legal, moral and behavioral fulcrum of the state. Constantine named himself Constantine the Great, establishing himself as a human deity at the head of the Church. This structure was later transposed to "Popes" and worked very well for the power elite for many years. It gave the contemporary Catholic Church a strong root system from which to grow.
That all changed during the 16th century after the invention of the Gutenberg Press, which established the era of mass communication. Literacy rates exploded and the renaissance ensued, as people were able to communicate more freely. In particular, the spread of the Bible became the initial text to be reprinted. This allowed individuals to become more acquainted with the scriptures as opposed to having the scriptures read and explained by authorities of the Church.
This individual reassessment of the Bible gave rise to the Protestant Reformation. The reformation, driven largely by the writings of Martin Luther (Lutheranism) and John Calvin (Calvinism), offered an alternative view of religion and the relationship of the soul to the Creator. A particular note of protestant discord was anchored in the Roman Catholic Church's self-appointed authority to allow indulgences because of its self-proclaimed unique relationship with God and Jesus. The protestant position was that the unique relationship was between the individual and God, usurping the Church's power over the people.
An alternative view advanced by some in the 'Net media focuses on covert funding of Luther and Calvin by the power elite of the day. These views claim that the power elite of the day created these religious movements to attack the Catholic Church and split its power.
While this viewpoint may indeed have some truth, the information revolution itself probably had an impact on these machinations. In other words, the Renaissance and the revolution of scientific inquiry was likely going to cause schism anyway. Those in the top ranks of European banking power merely exacerbated what was already predictable and tried to turn it to their own purposes. This they did with partial, though not entire, success.
This revolt eventually led to the Peace of Westphalia, which included negotiations between all of the nobility and royalty of Europe, along with authorities from the Roman Catholic Church and the Holy Roman Empire, including the Emperor. The alliances opened the way for the current structure of religion worldwide and the national structure of conventional Europe.