Marsilius of Padua (märsĭlˈēəs, păˈdyōə) [key], d. c.1342, Italian political philosopher. He is satirically called Marsiglio. Little is known with certainty of his life except that he was rector of the Univ. of Paris c.1312. When Holy Roman Emperor Louis IV was seeking a theorist to assist him in his struggle with Pope John XXII, Marsilius composed a tract, Defensor pacis [the defender of peace], probably in collaboration with the Averroist John of Jandun. It was published in 1324 and proved to be one of the most revolutionary of medieval documents. The work held that all power is derived from the people and their ruler is only their delegate; there is no law but the popular will, as expressed in the ruler. The church too has no authority apart from the people, and the actual power of the Holy See is self-arrogated; the church should be under the ruler, its province should be purely that of worship, and it should be governed by periodic councils. The notion that princes derive their power from the people was current in scholasticism, but the antiecclesiastical argument of the work aroused great scandal. It was repeatedly condemned by the Holy See. Marsilius, however, continued under the emperor's protection and went in Louis's train to Rome for his coronation and attended him afterward. His lesser works include an argument that the emperor had final jurisdiction in matrimonial cases (1342). The Defensor pacis had a long life; John Gerson recommended it, and in England, during Henry VIII's fight with the church, Thomas Cromwell patronized its translation into English (1535).
See the modern edition of A. Gewirth (1967); also A. Gewirth, Marsilius of Padua and Medieval Political Philosophy (1951).