This chapter underlines the various ways in which closer study of the Middle Ages can be relevant to some aspects of Western attitudes towards Islam, past and present. Taking the variability of the terminology used to name Muslims in medieval Iberia as a case study, the paper examines how the nomenclature used to designate Muslims was in specific instances influenced by understandings of Islamic ethnic and political complexities, as represented in works by medieval Hispanic writers and records of the decisions and deeds of leading Christian political figures. Understanding Islam to be a constellation of peoples had an impact on the responses of medieval Spaniards to local Muslim communities and leaders. Such nuanced understandings could also foster notably co-operative political relationships and arrangements. Analysing in particular the refinement of pre-Islamic Christian models for nomenclature with the Hispanic introduction of new designations during the first half of the twelfth century, the chapter shows that Christian authors could conceive of the Islamic world not just as a totalized vision of an abstract enemy, but also as a juxtaposition of peoples, and of political identifications in particular. These distinctions challenge the commonly held idea of the Middle Ages as a period of only crude intercultural understandings. They resonate with contemporary debates surrounding the place of Islam in the so-called modern world, a debate too often fed by a monolithic appreciation of what it is to be a Muslim.