Marsilius of Padua in Italian, Marsilio dei Mainardini (1275/80–1342), Italian political theorist. He served as rector of the University of Paris between 1312 and 1313; his anti-papal views forced him to flee Paris (1326) for Nuremberg, where he was political and ecclesiastic adviser of Louis of Bavaria. His major work, Defensor pacis (‘Defender of Peace,’ 1324), attacks the doctrine of the supremacy of the pope and argues that the authority of a secular ruler elected to represent the people is superior to the authority of the papacy and priesthood in both temporal and spiritual affairs. Three basic claims of Marsilius’s theory are that reason, not instinct or God, allows us to know what is just and conduces to the flourishing of human society; that governments need to enforce obedience to the laws by coercive measures; and that political power ultimately resides in the people. He was influenced by Aristotle’s ideal of the state as necessary to foster human flourishing. His thought is regarded as a major step in the history of political philosophy and one of the first defenses of republicanism. P.Gar.