abstract: This dissertation research employs biological distance and mortuary analyses in tandem with historical sources to investigate the degree to which conversion, as opposed to migration, contributed to the spread of Islam in southern Iberia. The dynamics of the 8th century conquest of Iberia by Muslim Arab and Berber forces from North Africa, and the subsequent 800-year period of religious, political, and social change, remain contested and poorly understood. Migration of Islamic peoples to the peninsula once was invoked as the primary vehicle of Islamic influence, but religious conversion, whether true or nominal, increasingly is regarded as a key component of those changes. This dissertation proposes that conversion, whether a prelude to or a component of Islamization, altered social group affiliations and interactions among those living in southern Iberia. Such changes in social relations and the resultant patterns of mate exchange will be recognizable by means of altered biological patterns of phenotypic variation. Through the examination of ~900 individuals from both Iberian and North African skeletal collections, this study concludes that conquest resulted in a great increase in phenotypic variability in the peninsula from the 8th-11th centuries. The data further indicate that males contributed this phenotypic variability to the samples in the Early Conquest period. Females, most frequently from Hispano-Roman Christian groups, appear to have ‘intermarried’ with these early conquerors and with the Muwallads, male Islamic converts, and are included in the early Muslim burial programs. From the 11th to the 14th centuries, the data presented here demonstrate a stasis and even a slight decrease in phenotypic variability in southern Iberia, which may be explained by endogamy among religious groups in this region. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2017