he Reformation began as an attempt to reform the Roman Catholic Church, by priests who opposed what they perceived as false doctrines and ecclesiastic malpractice—especially the teaching and the sale of indulgences or the abuses thereof, and simony, the selling and buying of clerical offices—that the reformers saw as evidence of the systemic corruption of the Church's Roman Catholic Church hierarchy, which included the Pope.
In Germany, reformation ideals developed in 1517-1521 when Martin Luther expressed doubts over the legitimacy of indulgences and the plenitudo potestatis of the pope. Martin Luther's excommunication on 3 January 1521, from the Catholic Church, was a main cause for the Protestant Reformation.
Martin Luther's spiritual predecessors included John Wycliffe and Jan Hus, who likewise had attempted to reform the Roman Catholic Church. The Protestant Reformation began the All Hallows' Eve of 31 October 1517, in Wittenberg, Electorate of Saxony, where Martin Luther nailed his Ninety-Five Theses on the Power and Efficacy of Indulgences to the door of the Castle Church, in Wittenberg. The theses debated and criticised the Church and the Pope, but concentrated upon the selling of indulgences and doctrinal policies about purgatory, particular judgment, and the authority of the Pope. He would later in the period 1517-1521 write works on the Catholic devotion to Mary, "The Mother of God", the intercession of and devotion to the saints, the sacraments, the mandatory clerical celibacy, monasticism, further on the authority of the Pope, the ecclesiastical Ban (Law), Censure and Excommunication, the prerogatives of the secular rulers in religious