Marsilius of Padua (Marsilio dei Mainardini), an Italian political theorist, was born between 1275 and 1280 and died in 1342. He probably studied medicine at the University of Padua. In 1313 he was rector of the University of Paris, where he met such leading Averroists as Peter of Abano and John of Jandun. He is chiefly famous for his antipapalist treatise Defensor Pacis (Defender of peace; 1324), a landmark in the history of political philosophy. When his authorship of this work became known in 1326, he was forced to flee to the court of Louis of Bavaria in Nuremberg; Pope John XXII thereupon branded him a heretic. Marsilius subsequently assisted Louis in various imperial ventures in Italy.

Defensor Pacis

The primary purpose of the Defensor Pacis was to refute the papalist claims to "plenitude of power" as these claims had been advanced by Pope Innocent IV...