Despite earlier attempts, Martin Luther started the Reformation in 1517 with his "Ninety-Five Theses". Luther criticized the selling of indulgences and that the Catholic doctrine of the merits of the saints had no foundation in the gospel. The "Protestants" soon incorporated doctrinal changes such as Sola Scriptura and Sola Fide. The changes were not only theological, but also other factors played a role in the Reformation: the rise of nationalism, the Western Schism that eroded people''s faith in the Papacy, the perceived corruption of the Roman Curia, the impact of humanism, and the new learning of the Renaissance that questioned much of traditional thought. The Roman Catholic Church responded with a Counter-Reformation initiated by the Council of Trent.
In Sola Fide: The Reformation, two players attempt to install Reformation in the Holy Roman Empire or try to prevent it, battling the Holy Roman Empire´s Imperial Circles, playing respectively as either the Protestant movement or the Catholic establishment.