The Reformation of the 16th century, which shook the Roman Catholic Church, was to be expected. Reformers within the medieval church such as St. Francis, Peter Waldo, Jan Hus, and John Wycliffe spoke about church abuses well before 1517. In the 16th century, the great Humanist scholar Erasmus of Rotterdam proposed some liberal Catholic reforms that attacked moral abuses and popular superstitions in the church and urged the imitation of Christ. This reveals an ongoing concern for reform within the church in the years before Luther is said to have posted his Ninety-five Theses on the door of the Castle Church in Wittenberg, on Oct. 31, 1517, the traditional date for the beginning of the Reformation. Martin Luther claimed that while previous reformers attacked corruption in the life of the church, he went to the theological root of the problem —the perversion of the church’s doctrine of redemption and grace. Luther, a pastor and professor at the University of Wittenberg, was against mixing God’s free gift of grace in a complex system of indulgences and good works. In his Ninety-five Theses, he attacked the indulgence system, insisting that the pope had no authority over purgatory, and that the doctrine of the merits of the saints had no foundation in the Gospels. According to Luther, Scripture alone is authoritative and justification is by faith, not by works. He did not intend to break with the Catholic Church but, as Luther was tried before the Imperial Diet of Worms and was eventually excommunicated, what began as an internal reform movement became a schism within the Roman Catholic Church.
The Reformation spread to other European countries during the 16th century. Lutheranism soon dominated northern Europe while Eastern Europe offered a seedbed for even more radical varieties of Protestantism. Spain and Italy were to be the great centres of the Counter-Reformation, and Protestantism never gained a strong foothold there. Following the Luther’s reformation, hundred of reformed churches with slightly different doctrines and rituals were formed with the result that these churches remained relatively small and never became universal, a qualification that, up to these days, remains attached to the Roman Catholic Church.