This is the first of two chapters concerned with the Jewish practice of infant male circumcision. In this chapter, I trace the history of circumcision as a trope for Jewish difference in European Christian thought and consider its symbolic role in debates about the legal equality of Jews. Christian thinkers spent much time pondering Jewish circumcision and what it told them about the supposedly ‘carnal’, particularistic, and anachronistic nature of Jews. Apart from constituting a trope for what differentiated Jews from Christians, the bodily sign eventually also became enmeshed in discussions about the possibility of Jewish emancipation where it offered a site to debate the fitness of Jews to become citizens. However, regardless of how much Christians disdained circumcision, they mostly respected the Jewish right to circumcise and due to a curious twist of history, some Christian societies eventually even embraced circumcision themselves. More recently, circumcision has emerged as a human rights issue and I explore the role of Christian ambivalence in contemporary calls for a ban on the practice in the name of children’s rights and gender equality.