The medieval period, which for this study is defined as between the tenth and the seventeenth centuries, was a time of violence and prejudice as Christian society became increasingly intolerant, especially from the twelfth century, not just toward Jews but toward everyone deemed deviant.

In the chapter on the church fathers we noted that Jewish rights granted by the Theodosian and Justinian Codes were progressively removed. In the medieval period this process accelerated. Legislation enabled local authorities to outlaw Judaism, close synagogues and enforce baptisms (despite some church council opposition). For example, the Fourth Lateran Council in 1215 addressed a variety of political and doctrinal issues, including the position of Jews in Christendom. Some laws were renewed, such as the law forbidding Jews to appear in public during Easter, especially on Good Friday (a ruling said to prevent mocking of Christians but also perhaps partly for the Jews' own protection). Other laws were new, such as that which compelled Jews (and Muslims living under Christian rule) to wear distinctive dress, in order to avoid ‘prohibited intercourse’ (especially sexual relations).

The practice of demarcating a religious minority by requiring its members to wear distinctive clothes originated in Islam, which imposed dress restrictions on both Jews and Christians in the time of Omar II (717–20). When discriminatory dress regulations entered Christian canon law in 1215, it testified to a society in which it was assumed that the category to which every individual belonged (nobles, serfs, clergy, etc.) should be identifiable by dress.