The Reformation began as a theological movement within the Catholic Church in the 16th century. Martin Luther's 95 Theses criticized corrupt practices in the Catholic Church and advocated salvation by faith alone. John Calvin also broke from the Catholic Church and established a theocratic republic in Geneva based on predestination and the authority of scripture over the Church. In response, the Catholic Church convened the Council of Trent to reaffirm Catholic doctrine and enact reforms via the Counter-Reformation. The Reformation transformed Europe intellectually, socially, and politically by challenging the authority of the Pope and encouraging national identities.