The Counter-Reformation was Roman Catholicism’s response to the Protestant Reformation. In the late 15th and early 16th centuries, Christians began to openly criticize the Roman Catholic Church for teaching things contrary to the Bible. The Reformers objected to the veneration (worship) of Mary, the selling of indulgences, the insistence that rituals and sacraments were necessary for salvation, and so forth. As the Reformation took hold culturally and theologically, Catholicism responded with its own efforts. Some of these were intended to change the Catholic Church itself, but most were designed to resist the claims of the Reformers. Collectively, these Catholic efforts became known as the Counter-Reformation.
In truth, the Counter-Reformation wasn’t really much of a “reformation” of Catholicism, at least not from a theological perspective. It was truly a “counter to the Reformation”; that is, it was primarily concerned with refuting and silencing Protestant disagreements. Much of the Counter-Reformation was driven by politics. In Spain, for example, kings and queens were more than happy to apply Catholic resources toward stamping out dissenters—in their case, mostly Protestants. Deportation, excommunication, and execution were common tools used in the Counter-Reformation.
Two lasting effects came out of the Counter-Reformation: the Jesuit Order (the Society of Jesus) and the Council of Trent.
The Jesuits are a religious order formed specifically to counter Protestantism. Their tactics during the Counter-Reformation involved intellectual and theological arguments, although they also used less spiritual methods of accomplishing their goals. The Inquisition was a product of Jesuit influence. The Jesuits also produced an Index of Prohibited Books: texts Catholics were officially forbidden to read. The Jesuits’ influence on Catholic philosophy and theology was significant.
The Council of Trent was, in theory, an attempt to change those aspects of Catholicism that Protestants were justified in complaining about. Unfortunately, the council itself came far too late. By the time the council convened, the Reformation had been in full swing for nearly a quarter-century. By that time, the church was well and truly split.
The Council of Trent did positively address some complaints of the Reformers. The sale of indulgences was stopped, the roles of priests were more carefully defined, and the use of sacred artifacts—relics—was greatly reduced. Certain aspects of music and liturgy and other practical issues were discussed as well.
However, on the most critical issues, the Council of Trent, like the rest of the Counter-Reformation, was mostly a doubling-down on entrenched Catholic theology. This council, and the other Counter-Reformers, doggedly defended transubstantiation, upheld the necessity of sacraments for salvation, rejected sola fide, and claimed outright that Catholic tradition was as equally authoritative as the Bible. In addition, the council members determined that the Latin Vulgate was the one and only acceptable Bible for church use. And they insisted that, since politics was instituted by God, all political leaders were subject to papal authority.
Even though some aspects of the Counter-Reformation were aimed at repairing broken parts of Catholicism, the primary effect was to stabilize and reinforce Catholic errors. It would be fair to say that the Counter-Reformation, especially the founding of the Jesuits and the results of the Council of Trent, slammed the door shut on any possible reconciliation with Protestantism or the Reformers.