Background and causes of the Reformation

The Protestant Reformation formally erupted in 1517 with Martin Luther's Ninety-Five Theses, though its causes stretched back decades. The corruption and nepotism of the Renaissance papacy, under popes such as Alexander VI, Julius II, and Leo X, bred deep resentment among reform-minded clergy and laypeople, and the sale of indulgences, intensified to finance the construction of the new St. Peter's Basilica, became the immediate trigger for Luther's protest. Renaissance humanism and the philological study of Scripture, exemplified by Erasmus of Rotterdam's "Novum Instrumentum" (1516), supplied reformers with critical tools, while Gutenberg's movable-type printing press, developed around 1450, made possible the mass, rapid distribution of pamphlets and Bible translations that proved essential to the Reformation's success. German national sentiment, resentful of the drain of resources to Rome, fueled support for Luther among princes and free cities, and the rise of an urban bourgeoisie with more individualistic religious sensibilities made society more receptive to reforming doctrines.