In order to understand Marsilius more fully, it is useful to examine both the classical influences upon his work and the ways he applies his own principles in the minor works such as Defensor Minor and De Translatione Imperii.

Marsilius and Dcicero

Most discussions of Defensor Pacis concentrate upon Aristotle's Ethics and Politics (which had become available in translation around 1250 and 1260, respectively). Indeed, Marsilius employs the Aristotelian distinctions of the healthy types of civil constitution: monarchy, aristocracy, and polity and their complements the diseased constitutions: tyranny, oligarchy, and extreme democracy. However, though Aristotle is certainly the primary source of many of the distinctions in Part I of Defensor Pacis, there are other key influences as well. Among these is Cicero's doctrine of natural duty to others from his De officiis. Cary Nederham has argued that this sense of natural duty is the...