How did the Roman Catholic Church respond to the spread of Protestantism?
First by banning and excommunicating, Then military force and the counter reformation.
The first effort to stop the spread of protestantism was to declare the effort to reform the Catholic Church a heresy. People who supported the protests of the sale of indulgences and other practice perceived by the protesters as unbiblical were excommunicated. According to Catholic theology being excommunicated put the person's salvation in jeopardy and removed the person from economic and political participation in the Catholic dominated society of Western Europe.
The technique of banning and excommunication worked to destroy the Lollard movement started by John Wycliff. After Wycliff died in 1384 his translation of the Bible into English was used to spread the reformation ideals of Wycliff. By 1400 10-50% of England had joined the Lollard movement. In 1408 The Catholic Church declared the Lollards heretics and encouraged their persecutions, loss of wealth and even death. By 1438 the Lollard movement was dead.
The German nobles protected Martin Luther from the executions by the state that typically followed a person being declared a heretic in 1521.and being an unrepentant excommunicate Luther was subject to a death sentence. Jon Hus was burned at the state by the secular court in 1415 after being declared an unrepentant heretic. When the banning and excommunication did not work. The Catholic church used two other approaches. Military might and the Counter reformation.
The reformation movement of the Waldensians was destroyed by a military Crusade called for by Pope Innocent II in 1208. The Hussite followers of Jon Hus also experienced a military campaign against them. The 30 years wars from 1618-1648 was another effort to use military might to stop the spread of a reformation effort against the Catholic Church. The Catholic nations such as Spain and France attacked the followers of Martin Luther, who were protected by the Protestant nations such as Sweden and Germany. The 30 years war ended in a draw with Protestantism intact.
The counter reformation was more successful. Starting in the Council of Trent from 145 - 1563 The Catholic Church reformed itself. The sale of indulgences was halted. The priests were required to be better education and held to a higher standard of spiritual discipline. The laity was provided with greater participation in the church. the Counter Reformation continued until the end of the 30 years war. Poland that had become protestant returned to the Catholic Church. The protestant movement of the Calvinist in France failed partially due to the Counter Reformation.
At first the Catholic Church reverted to the historic practices of banning and excommunication, followed by military repression. When these methods failed to stop the spread of Protestantism the Catholic Church turned to the Counter Reformation.