Marsilius of Padua and the Defense of Secular Sovereignty

Marsilius of Padua (c. 1275–1342), an Italian physician and philosopher trained partly in medicine at Padua and Paris, served as rector of the University of Paris in 1312–1313 before turning to the political treatise for which he is remembered, the Defensor Pacis (Defender of the Peace), completed in Paris in June 1324. The work is divided into two principal discourses (dictiones), the first setting out a naturalistic Aristotelian theory of the state grounded in Aristotle's Politics, and the second applying that theory in an extended, systematic critique of papal claims to supreme temporal and spiritual jurisdiction (plenitudo potestatis). Some scholars have argued, on grounds of style and content, that the Parisian arts master John of Jandun contributed to at least parts of the treatise, though the work has traditionally been attributed to Marsilius as its principal author.