Centered in the Ottoman province of Tunis, Sites of Servitude compares two groups of enslaved people and their descendants: individuals with presumed social origins in the Mediterranean island of Tabarqua (Ṭabarqīn), and individuals with presumed social origins in West and Central West Africa (ʿAbīd). This project unfolds from the premise that maritime exchanges of Mediterranean captives served as significant engines of wealth for rulers and notables of both Christian and Muslim kingdoms through the mid-18th century. Tunis also operated as a major terminus for the Trans-Saharan trade in West and Central West African captives, a trade that escalated over the late-18th and 19th centuries while Mediterranean corsairing receded. Notably, by the early 19th century, individuals once marginalized and enslaved as stateless Mediterranean “Ṭabarqīn” were able to ascend into higher social strata of Tunisian society, particularly the royal household and bureaucracy, compared to individuals of presumed sub-Saharan African descent. Sites of Servitude asks: why did this dramatic change in fortunes take place for the Ṭabarqīn, and not for the ʿAbīd? What can a social, cultural, and environmental history of enslaved people and their descendants tell us about broader shifts to notions of enslaveability in Tunis, and beyond? I contend that such a phenomenon was possible because of two intersecting transformations: exclusive legal protections afforded to “Ṭabarqīn” by the early 19th century, and the emergence of anti-Black racist ideologies crystallizing transimperially in Ottoman Tunis, Europe, and lands across the globe increasingly exploited by European empires by the early 19th century. To support this claim, I have gathered diplomatic, literary, fiscal, environmental, and administrative sources scattered across public and private (religious) archives in Tunisia, France, Italy, and England. Employing close-readings to examine markers of “difference” in human categorization, this project amplifies the archival presence and rich complexity of subaltern actors, even within dehumanizing documents. Sites of Servitude ultimately charts new ways of thinking about comparative slavery, informal imperialism, and transformations to ideologies of difference and belonging.