As the epigraphs above illustrate, it was a commonplace in late medieval texts to describe the depth of a heretic's depravity by relationship to that of Jews, Muslims, or pagans, and the language used to do this seems to have intensified during the first half of the thirteenth century. R. I. Moore's The Formation of a Persecuting Society (1987) notably made the case that new efforts to identify heretics, Jews, and other ‘marginalized’ groups of people as threats to Christian society in the twelfth century served an important social function in the construction of a new Christian body politic. In the decades since its publication, scholars have pushed back against some aspects of Moore's structuralist reading of the rise of inquisition and isolation of ‘outsiders’, but the notion that the twelfth century saw a new and fundamental linkage between Jews, heretics, Muslims, and other so-called marginal groups remains strong. Recent surveys of medieval heresy by Jennifer Kolpacoff Deane and Christine Caldwell Ames represent the state of the field well, and both embrace the notion that medieval Christians understood various categories of person to be members of a broadly construed group of ‘the infidel’.

There is good reason for the wide acceptance of this framework; the language of canon law texts and commentaries, theological treatises, and judicial and political policies all provide plentiful support for it.