A heretic is one who turns away from orthodoxy, from correct teaching. Normally defined, a heretic obdurately clings to their own ideas about the right path, even when it contradicts established authority and canonical texts. A heresy can only be said to exist when it can be contrasted against a norm. Without a norm against which it can be defined, heresy is simply a set of beliefs, a mode of worship, or a ritual practice. My point is that heresy never simply is, but needs to be categorized and defined in order to exist. It is no wonder, then, that the rise of scholastic theology coincided with what R. I. Moore famously argued was the development of the “persecuting society” in the Latin West. The period of the High Middle Ages saw the codification of law and theology, in which previously unwritten or diffuse laws and ideas were transformed into bounded systems of knowledge. In so doing the division between heresy and orthodoxy, or between criminality and legality, became much starker. The persecuting society, as defined by Moore, was one where authorities deployed these new definitions of orthodoxy in order to divide populations between the saved and the unsaved, the faithful and the deviant. In this way, Moore argued persuasively, authorities could bolster their own authority by defining an other against which the Christian subject could be defined. As we still see today, the demonization of difference enables the production of a political imaginary that privileges purity and righteousness. It was no different in the Middle Ages.

Paul wrote to the Corinthians, “For there must be also heresies: that they which are approved, may be made manifest among you” (1. Cor. 11:19). The demarcation of heresy was necessary to the making of Christian orthodoxy. The heretic, in fact, enabled the definition of the faithful. From the beginning of Christianity, doctrines were formulated and refined through processes of argument and contestation. Most notably, core aspects of both Trinitarian and Incarnational theology were established in the period between 100 and 450 CE. The process of making doctrine was one in which some forms of Christian worship and belief were declared orthodox, and some were demarcated as erroneous. During the Patristic era there were myriad christianities, with a likewise myriad set of beliefs, devotional practices, and rituals.