Located on the river Scheldt in the southern Low Countries, Antwerp of the sixteenth century was a vibrant and lucrative mercantile centre.1 Its commercial importance attracted merchants from all corners of the early modern world, including a large community of Portuguese New Christians, who used the port city as a midpoint in the transport of expensive spices from the Portuguese Indies to the Ottoman Empire.2 e New Christians seem to have been well integrated into both the civic and religious life of Antwerp. e extant documentation of the period suggests that they participated regularly in Antwerp’s frequent religious processions and were among the more generous donors to the city’s Christian charitable institutions.3 It would appear that the Portuguese needed to exercise few explicit ‘tactics of inclusion’ in order to be accepted into sixteenth-century society. e city welcomed them, surely in large part for their nancial contributions to the common weal, and they repaid their hosts in kind, by serving as model citizens and generous civic contributors. eir integration into the community was threatened, however, in the 1530s, when accusations emerged that some of the Portuguese New Christians were actually ‘crypto-Jews’, who lived ostensibly Christian lives but practised Judaism secretly and encouraged others to do the same. ese accusations set in motion a lively string of negotiations between the New Christians themselves, Emperor Charles V, his queen regent, Mary of Hungary, and the city council of Antwerp.4 During the course of these negotiations, the Antwerp fathers adopted a variety of strategies to defend their New Christian inhabitants. Indeed, they argued in favour of extending various forms of religious forbearance to these valuable merchants, to the point that religious toleration actually became one of their strategies for inclusion of this problematic ‘other’ within their midst. In this particular case, then, the presence of a heterodox religious minority actually served as a catalyst for the development of religious toleration.