In his effort to fashion a Christian prince in the Institutio principis Christiani, Erasmus, always the pedagogue, considers not only what the young ruler should read but how he should read it-that is, according to what interpretive method. The principal text on this reading list is the Bible, which, depending on the specific passage in question, bears reading in one of two ways: either allegorically or in the particularized light of a different time and place, what Erasmus refers to here as pro ratione temporis -after the standards of the time. While Erasmus does not on this occasion explain the similarities and differences between these two methods, elsewhere in his writings he elaborates upon their proper use and, especially in the case of allegory, their excesses. This essay, however, undertakes to explore only one of these two methods: interpretation pro ratione temporis, or what I have called Erasmian historicism. More precisely, I intend to show that, on the one hand, Erasmus distances this method from a rigid literalism that attends only to the words themselves, while, on the other hand, he identifies it repeatedly with the legal and rhetorical concept of equity. By doing so, he forges a method of interpretation that sets out to accomplish two seemingly contradictory tasks: it aims not only to preserve the original meaning of a text (as allegorical interpretation, according to its critics, fails to do) but also to accommodate a continually changing community of interpreters (as allegorical interpretation characteristically does). To fashion such a method, Erasmus looks back to the ancient rhetorical tradition, and more particularly, to its strategies of forensic debate. In keeping with these agonistic origins, moreover, Erasmian historicism serves as a powerful instrument of dissent.