Thus throughout the fifteenth century and the early part of the sixteenth, much was heard from scholars, princes, and people, of the need for "reformation" of the Church. That did not signify a change of the old regulations but rather their restoration and enforcement. For a long time it was not a question of abolishing the authority of the pope, or altering ecclesiastical organization, or changing creeds. It was merely a question of reforming the lives of the clergy and of suppressing the means by which Italians drew money from other nations. [Sidenote: Religious Causes of Protestant Revolt] In the sixteenth century, however, a group of religious leaders, such as Luther, Cranmer, Zwingli, Calvin, and Knox, went much further than Erasmus and the majority of the humanists had gone: they applied the word "reformation" not only to a reform in morals but to an open break which they made with the government and doctrines of the Catholic Church. The new theology, which these reformers championed, was derived mainly from the teachings of such heretics as Wycliffe and Hus and was supposed to depend directly upon the Bible rather than upon the Church. The religious causes of the Protestant Revolt accordingly may be summed up as: first, the existence of abuses within the Catholic Church; second, the attacks of distinguished men upon the immorality and worldliness of the Catholic clergy; and third, the substitution by certain religious leaders of new doctrines and practices, which were presumed to have been authorized by the Bible, but which were at variance with those of the medieval Church. [Sidenote: Date and Extent of the Protestant Revolt] For the great variety of reasons, which we have now indicated,-- political, economic, and religious,--the peoples of northern Germany, Scandinavia, the Dutch Netherlands, most of Switzerland, Scotland, England, and a part of France and of Hungary, separated themselves, between the years 1520 and 1570, from the great religious and political body which had been known historically for over a thousand years as the Catholic Christian Church. The name "Protestant" was first applied exclusively to those followers of Martin Luther in the Holy Roman Empire who in 1529 protested against an attempt of the Diet of Speyer to prevent the introduction of religious novelties, but subsequently the word passed into common parlance among historians and the general reading public as betokening all Christians who rejected the papal supremacy and who were not in communion with the Orthodox Church of eastern Europe. Of this Protestant Christianity three main forms appeared in the sixteenth century--Lutheranism, Calvinism, and Anglicanism. Concerning the origin and development of each one of these major forms, a brief sketch must be given. LUTHERANISM [Sidenote: Martin Luther]