Religious Turmoil in 16th Century Europe
The Great Peasant Revolt and Thomas Muntzer
The background against which the revolt occurred was an ever increasing squeezing of the peasantry by both the secular and scared rulers. So much land had been declared noble possessions that many peasants had no place where they could legally gather wood or fish. Church officials often charged peasants for their services and sold indulgences at rates that they really couldn't afford. Even given all this, the peasant revolts may have remained small and scattered where it not for the presence of Thomas Muntzer.
Thomas Muntzer was a priest at Braunschweig in Thuringia. He came to strongly identify with the peasant's grievances and his message, that all things should be held in common for the benefit of all, was just the message the peasants wanted to hear. His famous pamphlet, All in Common, was spread widely throughout the Holy Roman Empire.
Muntzer was an extreme anti-cleric, denouncing the clergy for their moral laxity, spiritual impotence, and their oppression of the common people. Another of his famous works, Of the Priesthood of all Believers, amounted to a rejection of the whole administrative structure of the church. He stressed that every believer had the right to administer the sacraments, or even to preach if the were called by God - no appointment by man was needed.
Fanned by Muntzer's ideas, by 1522 large revolts were present not only in Thuringia, but Saxony, Hesse, Palatinate, and Swabia as well. Emperor Charles V, who was facing a French incursion into Italy and a major threat from the Ottomans, was initially unable to respond to the revolt.
By 1523, the peasants had defeated several small imperial forces and had begun to organize a system based on Muntzer's ideas of common holdings. Muntzer was heavily involved in this process, and emerged as the de facto leader of the movement. It was at this time that he popularized the idea of continual revelation, that God's revelation was not complete in the Bible nor handled by Church tradition, but that God speaks new truths to modern apostles.
Historians like to speculate what would have happened had the peasants been allowed to form a lasting government, but it was not to be. Still unable to bring most of his main force to bear, Charles IV nevertheless was able to raise an army of 20,000 consisting in large part of Swiss mercenaries. The army plundered it's way through the empire, as mercenary armies often did, and initially ran in to little in the way of resistance.
Muntzer was working to form a true army to oppose them, but the peasants were poorly armed and still poorly organized. He did manage to meet the mercenary army with a significant force (reported by temporary accounts at 50,000, although that is likely 3 or 4 times the true number) outside of Braunschweig on May 8, 1524. In the resulting battle, Muntzer was killed and the peasant army was dispersed, with the well-trained mercenary army taking few causalities. This ended the Great Revolt, although small disturbances would continue for some time. All told, an estimated 150,000 people died in the four-year conflagration.
Switzerland and a Precursor to Reformism
Before the disturbance to the north was put down, a new one just getting started in Switzerland. It was launched in 1523 when Ulrich Zwingli convinced the Zurich town council to adopt his proto-reformation views. Some point to an influence from Muntzer in his ideas, but this has now been largely discredited. In any case, Zwingli was a much more consistent theologian than Muntzer, and was not at all as radical socially.
Zwingli viewed the Catholic Church as having been corrupted by tradition. He believed that anything that the Church did that was not supported by scripture should be ended. To this end he lead Zurich in stripping churches of icons and finery, promoting the marriage of clergy, and ensuring that priests were educated and of high moral character. Theologically, he opposed the Catholic doctrine of transubstantiation, teaching instead that the bread and wine at mass were only symbolic of the body and blood of Christ. He also oversaw the city takeover of church property and social work, and began the practice in paying the priests from the city's coffers.
Zurich sent priests to convert other Swiss cities to the views of Zwingli, and was successful in the case of Mulhouse and Berne. Other areas refused, perhaps associating these reforms with the peasant revolts to the north. This was a mistake as they were nothing alike; indeed, there are signs that Zurich clamped down harshly on a pro-Muntzer movement. Another factor may have been that Zwingli taught strongly against the mercenary practice, something that several of the Swiss cantons were economically depended upon. These factors lead to the Swiss Religious War of 1528.
The immediate cause of the war was the execution of a Zurich priest in the Canton of Unterwalden, leading to a declaration of war by Zurich, Mulhouse, and Berne. The other cantons took little time in deciding in favor of Unterwalden. The 3-city alliance was initially successful, winning the First Battle of Lake Lucerne over the army of Unterwalden. However, two days later (April 7), while they were still regrouping, they were attacked by the combined armies of Uri, Schwyz, Lucerne, and Zug, and were utterly defeated in the Second Battle of Lake Lucerne. Among the causalities was Zwingli himself, who died the next day. As part of the peace settlement, Zurich, Mulhouse, and Berne had to reverse their religious reforms, and thus Catholicism triumphed among the Swiss.