Of the two principal traditions of toleration theory in seventeenth-century Europe, what have been termed the ‘Arminian’ and the ‘republican’, the first culminates in Locke and the second in Spinoza. Both theories were products of the late seventeenth-century European intellectual ferment, both were deployed in England during the public debate about toleration in the aftermath of the Glorious Revolution, and both were destined to exert a pervasive influence in intellectual debate throughout Protestant and Catholic Europe during the eighteenth century. Yet an immense philosophical and ideological gulf separates the two – one might almost say rival – conceptions of toleration, a gulf which becomes greater the more it is considered. For if ‘we should be wary’, as Dr Davidson observes in chapter 12 of this volume, ‘of equating a call for religious toleration too easily with a call for unlimited freedom of belief’ it was generally true of Enlightenment Europe that religious toleration in the sense expounded by Le Clerc, Van Limborch and Locke, or at least something approaching it, gained much wider acceptance than did freedom of thought and expression in Spinoza's sense and that of the radical Deists. What was deemed the acceptable face of toleration, the toleration of Locke and Le Clerc, was aptly characterized by the Venetian theologian, Daniel Concina, in 1754, in a work identifying Spinoza and Spinozism as the backbone of the Deist threat to Christianity, as in essence a ‘tollerantismo between the Christian churches’.