This dissertation investigates the long and diverse lineages of medieval European engagement with the Mongol Empire from the Fifth Crusade (1217-1221) to the end of the fourteenth-century. It examines the literature this cross-cultural encounter produced, including historiography, travel narratives, and romances, in order to reveal the discursive practices by which racial ideologies were formed during the period under study. Existing scholarship on medieval ideologies of race has concentrated on representations of religious difference or descriptive analyses of physiognomic differences. At the same time, this work has been heavily scrutinized with charges of anachronism grounded in the idea that race is a modern phenomenon, a social construct engendered by the institutions of colonialism and transatlantic slavery. This project draws on the theories of race advanced by Geraldine Heng, taking the literary representation of Mongols as a case study to show how racial ideologies of the period were not limited to religion or the body. It argues that geopolitical circumstances led to the construction of Mongols as exotic allies, a term this project coins to define a racial formation characterized by the consolidation of fear, desire, and control. In using the conceptual framework of the exotic ally to analyze the racial function of Mongols, this project reveals the ontological features of medieval European racial ideologies and the role that global relations played in their formation.