There is still some ambiguity about the authorship of the book Defensor Pacts. When it was first printed in the sixteenth century it appeared under the name of Marsilio of Padua alone, and subsequent editors repeated the ascription of the editio princeps. For long, therefore, it passed as Marsilio's work. But evidence has since been brought to light suggesting that a certain John of Jandun had some sort of interest in the book too. That evidence has been very variously interpreted. On the one hand, Jandun has been treated as merely a copyist, the translator of the French version, or Marsilio's confidential adviser; but on the other, as a collaborator who furnished the quotations from Aristotle, or perhaps constructed some of the philosophical arguments. But what exactly his share was has yet to be determined.