Perhaps the most notorious passage in Machiavelli's Il Principe comes in Chapter 18, where the duplicity of the fox and the violence of the lion are set as models for political conduct, and where the author writes that, though a prince should conduct himself in accordance with the moral virtues when he can, “if the necessity arises, he should know how to follow evil.” These words have often been taken as a sign of Machiavelli's decisive break with the past, with biblical and classical traditions according to which the office of a prince was an inescapably moral one. Yet, in making these recommendations, Machiavelli was attempting to place his own teachings in an ancient tradition of secret political instruction. The legend of Achilles and Chiron the Centaur is his text: