The Protestant reformation posed a threat to the Catholic Church. In order to meet the challenge Pope Paul III and his successors introduced a number of rigorous reforms in the Church. They dealt with corruption severely and stopped the sale of offices. The Council of Trent reemphasized the importance of ceremonies and the significance of the mass. It also pronounced that only the Church could interpret the scriptures. Further, it revitalized the Inquisition to deal with opposition to the Church. It also gave official sanction to the Society of Jesus. This reformation of the Catholic Church from within is known as Counter Reformation.
St. Ignatius Loyola founded the Society of Jesus to propagate Christianity. Its main work was through education and service to the destitute. It started a number of educational institutions, orphanages and homes for the destitute. Soon their missionaries were present in all parts of the world to spread the Catholic religion.