Starting with the observation that there is a failure in an English language of “difference” associated with travel and trade in the late sixteenth century, this article explores the nature and consequences of that failure. Particular emphasis is placed on conversion—the evaluation and acceptance of an “alien” body into the Anglican community—and an analysis of John Foxe's A sermon preached at the christening of a certaine Iew (1578) and Meredith Hanmer's The Baptizing of a Turke (1586). Diplomatic and travel texts are considered to demonstrate the use of an earlier lexicon of heresy alongside contemporary ideas concerning the equivalence of Roman Catholicism, Judaism, and Islam. In the last decade or so many scholars have identified problems with the critical language in which these issues are discussed, in particular the notion of early modern England and its “others”. In evaluating the failure of a language of “difference,” this article suggests an alternative critical vocabulary.