Marsilius of Padua (c. 1275-c. 1342) was one of the most influential and controversial political thinkers of the Middle Ages. He is best known for his seminal text Defensor Pacis (1324) in which he attacks the papal theory of plenitude of power and defends an idea of political community based on the strict separation between political and religious authority. Marsilius' work lies at the crossroads of different disciplines, ranging from political philosophy to civil and canon law, to medicine. Indeed, he presents an original synthesis of several contemporary themes and traditions such as Aristotelianism, Augustinianism, the debate on Franciscan property, the communal tradition of the Italian city-states, ecclesiology, medicine, and astrology. This edited volume analyses the life and thought of Marsilius of Padua in his own context and beyond. Gathering most of the leading experts in Marsilian studies across different national and linguistic traditions working today, this volume has two main goals. First, it aims to bring together experts who come from distinct fields in order to investigate the many branches of knowledge present in Defensor Pacis without losing sight of Marsilius as a comprehensive theorist. Second, the volume aims to shed new light on one of the most neglected aspects in Marsilian studies: the Marsilian influence, i.e., his impact on the early modern period during the Renaissance, the Reformation and the Counter-Reformation, up to twentieth century.