The correct answer to this open question is the following.
Religious conflicts and changes caused turmoil in Europe from 1500 to 1750. Selling indulgencies represented a big business for the Catholic Church, that constructed a series of churches in the 1500s such as the St, Peter Basilique.
Then, in October 1517, German Monk Martin Luther started what is known as the Protestant Reformation, accusing the Catholic Church of corruptive practice such as the selling of indulgences. He expressed his concerns in the book "95 Theses." That is why in 1545, the Catholic Church initiated the Council of Trent to reevaluate the role of the Catholic Chruch in Europe.
This turmoil made some monarchies arise to power and put limits on the power of the church. Since the 1600s, the kings exerted power and control over the churches but allowed religion the maintain its powerful presence in society. We have the case of Henry VIII, King of England, when he appointed himself the leader of the Church of England.