How did the Catholic Church respond to the challenges of Luther, Calvin, and the Protestant movement?
In 1517, Martin Luther posted his 95 Theses to the door of All Saints' Church in Wittenberg, Germany. In these theses, Luther questioned the Catholic Church's sale of indulgences to reduce punishment in Purgatory for sins and argued that faith, not works, led to salvation.
The Catholic Church's first response to his theses was to summons him to Augsburg in 1518 to argue his position before Cardinal Thomas Cajeton. The debate with Cardinal Cajeton lasted three days, and Luther refused to retract his positions, leading Luther to need to escape arrest and imprisonment in Rome.
The Catholic Church's second response was for Pope Leo X, by 1520, to issue a papal bull declaring Luther's theses to be heretical. When Luther still did not retract his positions, he was excommunicated.
A third response of the Catholic Church was for Prince Frederick III, brother of Roman Emperor Charles V, to summons Luther to appear before the Imperial Diet, meaning assembly, at the Diet of Worms, in 1521. Here, Luther was asked by Johann Eck to defend the positions in his writings, which Luther did, including his rejection of the supremacy of the pope. The Diet of Worms led to Emperor Charles V issuing the Edict of Worms, forbidding anyone to support Luther upon punishment as a heretic.
After the bloody Peasants War raged from 1524 to 1525, the Catholic Church was forced to show tolerance to the emergence of Lutheranism. However, true peace was not established between Catholics and Protestants until the Treaty of Hamburg was signed after the Thirty Years' War ended in 1648, having begun in 1618.
The Catholic Church's immediate reaction to Martin Luther's Theses was actually quite mild, with many elements of the church agreeing with the need for reformation. The bishops, who disagreed with Luther, merely asked Luther's immediate superior to help calm him. However, the effects of the Theses spread far beyond that which was intended by Luther, namely the curbing of indulgences, and began to feed into a general discontent with the Catholic Church. With this sentiment growing rapidly, the Pope ordered crackdowns and, fearing to lose control, declared the dissidents heretics. It was only as a result of this persecution that Luther actually broke from Rome and was then targeted for inquisition. This eventually led to Luther's excommunication from Rome. However, by then Luther's teachings were highly popular within the Holy Roman Empire, popular enough that the emperor was willing to protect Luther. Therefore Luther was able to go to and from the Council of Worms unmolested. However, the power of Rome still held sway over the Holy Roman Empire, and Luther was declared an outlaw. Thereafter Luther translated the Bible into German, causing the spread of the Protestant movement. The Church continued to attempt to fight its spread, and tensions eventually led to the Thirty Years' War.
Calvinism was considered simply part of the Protestant movement by the Catholics and was not truly considered an independent entity.
However, the largest example of a Catholic response to the Reformation is the Counter-Reformation. The Counter-Reformation was a series of reforms aimed at addressing many of the concerns of the Theses and weakening the Protestant movement. While this did mitigate the effects of the Protestant Reformation, the tensions remained and resulted in the Thirty Years' War. The Thirty Years' War ended with the Peace of Westphalia, which guaranteed the rights of Protestants in Europe.
Martin Luther is credited with the initiation of the Protestant Reformation that was opposed by the Roman Catholic Church. Luther communicated his ideas through writings such as the Ninety-Five Theses, which eventually led to the clear disconnect between the Lutherans and the Catholics during the Diet of Worms where Luther refused to denounce his ideology and religious public remarks. The Catholic Church reacted by banning all citizens of the Holy Roman Empire from supporting Lutheranism at the pain of having their property taken away. Luther was declared an outlaw, and an order for his arrest was made. He was protected by Frederic III while he continued his reform agenda.
John Calvin was a controversial theologian and a reformer alongside Luther during the Reformation. Calvin left the Catholic Church after the violent persecution of Protestants in France. The Catholic Church, as expected, opposed the reformation and imposed strict penalties on supporters and forced some of them out of their territories. The hostile environment was only addressed by a raft of treaties, with the first targeting the Lutherans (Peace of Augsburg) and later the Calvinists (Peace of Westphalia).