The preparation for the movement was long. Opponents of orthodox views had asserted themselves over centuries, and in the 14th cent. John Wyclif had led a dissident movement. His ideas were amplified later by John Huss in Bohemia, who was burned (1415) at the stake by order of the Council of Constance. After his death his followers in Bohemia upheld his cause in the long and bitterly fought Hussite Wars. These dwindled into compromise, but Huss's challenge to the orthodox view of the Eucharist and the revolutionary effect of the wars did not disappear.
New forces fanned discontent with the church and the medieval order of society. There had long been outcries against abuses in the church, especially the blatant worldliness of some of the clergy, the emphasis on money, and the oppressiveness, not only intellectual but economic, of members of the church hierarchy. In the 15th cent. the conciliar movement (i.e., the attempt to establish the superiority of the ecumenical council over the pope) heralded the growing internal church dissent. Although the movement failed, the number of those wishing reform nevertheless grew steadily.
The desire for change was increased by the appearance of humanism and the spirit of the Renaissance. Study of the ancient Greek and Hebrew texts concentrated attention on the Bible and evoked a new critical spirit, exemplified in such men as Lorenzo Valla and Johann Reuchlin. The Renaissance also tended to develop an emphasis on the individual. The later humanists were outspoken in their attacks on the abuses in the church; Desiderius Erasmus was, perhaps, the most prominent, but there were many others, including the humanists at Oxford. The intimate connection between the new learning and the Reformation itself is shown in the pursuits of men who were to be prominent in the Reformation in central Europe; Ulrich von Hutten and Philip Melanchthon were outstanding figures in humanism, and Huldreich Zwingli arrived at opposition to the church mainly through the study of Greek and Hebrew. The very founding of the Univ. of Wittenberg, which was to be the center of revolt, was part of the urge to humanism.
The introduction of printing in Western Europe allowed more widespread dissemination of criticism. Printing was to hasten the Reformation, and the Reformation in turn was to spread printing further. In secular matters the opposition between church and state was centuries old, but it had begun to take a new turn with the building of strong nations. In Germany this opposition to the power of the church was coupled in the minds of many princes with opposition to that other supranational body, the Holy Roman Empire, and the princes were to play a decisive part in the ecclesiastical rebellion.
The rise of the cities and of the power of merchants and the middle class generally not only upset the old medieval order of things but created much discontent with the scholastic views on finance and economic affairs that fettered the enterprise of the men in search of wealth. The economy of Europe was expanding and forcing cracks in the more or less rigid walls of the system. Scholars of the 20th cent. have put a great deal of emphasis on the connection between the new modes of religious thought and economic change (i.e., the connection between Protestantism and capitalism) as a major force in the Reformation. There were, however, many influences at work, and the field was well prepared by 1517. Nevertheless, it was with suddenness and surprise that the Reformation began.