 The fourth treatise of the Convivio seems to have been written later than the first three, and it is markedly different in orientation. The principal theme of its canzone is the true nature of nobility. Introducing his prose discussion, Dante gives a curious account of how an interruption in his philosophical studies, caused by what the canzone calls “disdainful and harsh” behavior on the part of the donna gentile, provided an occasion for taking up this topic: