Disdain and mistrust of the Catholic Church was the major cause for the Protestant Reformation. Reformers particularly decried the selling of indulgences and offering of forgiveness for sins in exchange for money; the practice of selling religious positions in the church was also frowned upon by those who sought to reform the church.
The church before the Reformation was riddled with abuse. Popes were worldly and abuses within the ranks of the church ranged from nepotism to financial excess to simony, immorality and venality. The clergy tended to live scandalous and greedy lives.
Another point of criticism of the church at the time was that the common layperson didn't know much about Christianity, since the sermon was rendered in Latin that common people couldn't understand.
A turning point in the Reformation occurred when King Henry VIII of England broke with the Catholic Church after a dispute with the pope that involved his desire to divorce his first wife and take another. This led to the translation of the Bible into English, a language that made it more accessible to the common person.
As a result of the Reformation, Christendom was broken into two areas: Protestant and Catholic. National churches were established, including the Church of England, that still stand today. Counter-reformation attempts by the Catholic Church resulted in persecution of Protestants, many of which fled their European origins to make a new life in the New World.