Reformation (Christianity. Reformation, the religious revolution that took place in the Western church in the 16th century.
Its greatest leaders undoubtedly were Martin Luther and John Calvin. Having far-reaching political, economic, and social effects, the Reformation became the basis for the founding of Protestantism, one of the three major branches of Christianity. The Reformation Online - The Most Timely, Scientific, and Patriotic Site on the Internet. Protestant Reformation.
Although the core motivation behind these changes was theological, many other factors played a part, including the rise of nationalism, the Western Schism which eroded people's faith in the Papacy, the corruption of the Curia, and the new learning of the Renaissance which questioned much traditional thought.
On a technological level the invention of the printing press proved extremely significant in that it provided the means for the rapid dissemination of new ideas. The Roman Catholic Church responded with a Counter-Reformation initiated by the Council of Trent and spearheaded by the new order of the Society of Jesus (Jesuits) specifically organized to counter the Protestant movement. In general, Northern Europe, with the exception of most of Ireland, turned Protestant.