Medieval Christians constructed Islam and Judaism as mutual templates

Evidence

From this brief account, it is clear that Judaism was used as the template with which a distorted representation of Islam could be constructed. Yet, as we shall see in the case of the Siege of Jerusalem, the template could be applied the other way: Muslim identity could be used, at least in part, as the basis for the representation of Jewish identity. — Ivan Davidson Kalmar, Derek Penslar, Orientalism and the Jews, 235

Categorization

• XREF: connects to: By 1250 the unity-of-God doctrine was common Christian knowledge about Islam; Medieval authors mislabelled Islamic Christian and Jewish influences as heretical sects