This chapter uses case studies from fifteenth century Seville and sixteenth century Lima to examine how law informed such practices on both sides of the Atlantic and helped produce specific notions of identity. Muslims, Christians, and Jews had lived side by side for centuries on the Iberian Peninsula. While their religious and legal practices differed, most of their everyday life activities overlapped in a shared habitus. The New World was, at least initially, different. Spanish travelers identified social practices that they found exotic or threatening. While these differences might be exaggerated or invented, Spaniards and indigenous people were often mystified by each other’s everyday practices: ritual actions, the structures of work and governance, gender roles, forms of exchange and property relations, among others. Muslims and Jews posed a threat to Christian society in late medieval Castile due to what Christina Lee calls the anxiety of sameness, the inability to detect an interloper by visual inspection.