The treatise of Marsilia of Padua is part of the cultural heritage of mankind. The theoretical provisions of the author of the XIV century formed the basis of religious, ideological, political concepts of many later thinkers of the Reformation and Renaissance. During the dark Middle Ages, when the fires of the Inquisition were already burning in Western and Central Europe, Marsilius of Padua raised the issue of religious tolerance, insisted on the democratic reorganization of the Catholic Church and demanded its submission to the state. In his treatise, he shares the legislative and executive branches of state power, advocates the election of a secular ruler and his activities exclusively within the legal framework, justifies the need for the participation of the people in the development and approval of the laws of the state.