For hundreds of years, the Roman Catholic Church was the dominant religious power throughout Europe. Their rules of conduct and worship were strict, and not everyone agreed with them. To go against the Church was an unspoken taboo, but that was exactly what Martin Luther decided needed to be done.
Known as the father of Protestantism, Martin Luther was a German monk, theologian, and professor who disagreed with a few things about the Catholic Church. So much in disagreement was he that Martin Luther wrote down his gripes in the form of his 95 Theses and nailed them to the door of the local church.
Although the Theses pointed out several perceived flaws with how the Catholic Church functioned, the focal point of his criticisms was the sale of indulgences. At the time, the Church allowed its worshippers to pay away their sins and buy themselves a shorter stay in purgatory.
On June 15 of 1520, Pope Leo X informed Martin Luther that he risked excommunication if he did not recant his 95 Theses, along with several other lines of writing, within 60 days. By that time, the Theses had spread across Germany and had begun sowing the seeds of discord.
Martin Luther publicly refused to go back on his words. In a town square, he set fire to the bull that demanded his compliance and the document outlining which statements of his the Church disagreed with. On January 3, 1521, Pope Leo X issued another papal bull formally excommunicating Martin Luther from the Catholic Church.
Following his excommunication, Martin Luther established Protestantism. This new sect of Christianity revolved around many of the old tenets of the Catholic Church with one major adaptation. Protestant churches followed the belief that salvation could be achieved only through devout faith in Jesus Christ.
Since its creation, Protestantism has branched into several other sects with slightly different beliefs and practices. Lutheranism, of course, is a branch of Protestantism, as are Anabaptism (Mennonites), the Quaker Faith, the Latter Day Saint Movement, and Evangelicalism.