This dissertation examines the role of slavery to the development of the modern Ethiopian imperial state from the beginning of the reign of Emperor Tewodros II in 1855 until the promulgation of the 1957 Penal Code under Emperor Haile Selassie. Drawing upon a wide range of sources including European travelogues, Amharic literature, modern Ethiopian art, and legal records, it argues that slavery played more than an economic role in modern Ethiopian history. Slavery informed nineteenth and early twentieth century racial imperial hierarchies and underlined cultural notions of progress and civilization, while the abolition legislation of the twentieth century attempted to re-make Ethiopian subjects into citizens. Ethiopian imperial hierarchies organized the newly expanded empire into religiously defined racial hierarchies, which by the end of the nineteenth century informed and were shaped by a growing global color line. European travelers and Ethiopian imperial forces depended on enslaved and freed guides and translators from the borderlands to navigate these journeys and these borderland individuals shaped imperial and global racial logics. In the early twentieth century, Ethiopian intellectuals and artists grappled with their own place in global racial hierarchies and used their writing and art to assert their own notions of racial difference and belonging—often using enslaved black individuals as a foil for ‘civilized’ Christian Abyssinians. By the 1920s Ethiopian abolition legislation, influenced by international pressure at the League of Nations, attempted to re-make enslaved and freed Ethiopians into citizens. The promise of full citizenship and abolition for enslaved individuals remained elusive until the 1942, when the newly restored imperial government underwent a campaign to enforce abolition measures in the borderlands after the Italian occupation (1936-1941). Pardon petitions show a concerted effort to punish slavers in the 1940s, but the re-consolidated state emerged with a carceral regime increasingly concerned with controlling the movement of marginalized individuals. Though the state and intellectuals embraced Black internationalism and pan-Africanism after the Italian occupation, the imperial state failed to resolve its foundational religious-racial hierarchies of enslavement.