This project employs multiple methods to explore how shifting periods of autonomy during the Portuguese Middle Ages (c. 500-1500 AD) impacted the social and biological fabric of everyday life and post-mortem bodily integrity in religiously distinct communities. The archaeological materials from Santarém, Portugal offer an opportunity to facilitate a comparative approach, as many of the excavated cemetery sites within the municipality are a palimpsest, and contain members of distinct religious and temporal communities. This dissertation prioritizes two cemetery sites: Avenida 5 de Outubro (S.Av5Out; n = 164 burials) and Largo Cândido dos Reis (S.LCR; n = 622 burials) which contain the human skeletal remains of Islamic (c. 8th – 12th centuries, C.E.) and Christian (c. 12th – 16th centuries, C.E.) city residents. This project examines how religious identity might explain some of the variation within and between medieval communities through an investigation of both lived experience (lifeways) and death, dying, and burial treatment (deathways). Lifeways are examined through three major axes: 1) oral health and disease, 2) growth and development, and 3) cortical bone maintenance and loss. The data overall suggest minor differences between Islamic and Christian sub-samples, though Christians exhibited reduced stature, increased odds of some indicators of non-specific stress (porotic hyperostosis and periostosis), and dental pathological lesions. Deathways are similarly examined along three major axes: 1) post-hoc archaeothanatology, 2) macrotaphonomic indicators (preservation, erosion, weathering), and 3) microtaphonomy (histotaphonomy). Islamic and Christian burials were found to be highly different in terms of construction, with Islamic graves significantly narrower and shallower than their Christian counterparts. Islamic skeletons were also less represented, and significantly less preserved than their Christian counterparts, regardless of age and/or sex. The results of this dissertation are part of an emerging pattern that the Christian conquests (canonically termed “Reconquista”) may well have been drastic in their restructuring and urbanizing of the Iberian Peninsula, for both the living and the dead. By examining both lifeways and deathways, this approach and accompanying results demonstrate synthesizing both bioarchaeological assessments of livelihood and funerary taphonomic assessments of deadlihood can reveal more textured understanding of past communities and how the living and the dead become intertwined in urban spaces.