The document defines key terms related to the Protestant Reformation such as Protestant, sale of indulgences, Great Schism, Martin Luther, 95 Theses, Desiderius Erasmus, John Calvin, predestination, and Ignatius of Loyola. It provides brief explanations of individuals like Martin Luther who led the Protestant Reformation and challenged corrupt Catholic Church practices, and beliefs like Calvin's theory of predestination. The Reformation sought to reform the Catholic Church and led to the emergence of Protestantism as a new form of Christianity distinct from Catholicism.