The counter reformation was a religious movement organized by the Catholic Church as a response to the Reformation and the rise of Lutheranism.
In his 95 theses, Martin Luther discussed the flaws in the Catholic Church. Once citizens began to leave the church for Luther's, they started to make some changes in order to keep members in their church. This all started at the Council of Trent. The Council of Trent leads to reaffirming some parts of the Catholic Church (like keeping indulgences) but also results in the creation of Jesuits. Jesuits are individuals who spread the word of the church and focus more on spirituality and service to the church.
