According to the most recent figures, more than 400,000 African slaves are now estimated to have disembarked in Spanish American territories during the years of the Iberian Union (1581-1640). The vast majority of those captives arrived to America from West Central Africa, primarily via port of Luanda. This thesis explores the interconnection between the Portuguese occupation and colonization of Angola, and the development of the Iberian slave trade to Spanish America during the Union of Crowns (1581-1640). By focusing on Angola, a territory traditionally regarded as a periphery in the vast realm of the Habsburg Monarchy, I look at the evolution of the different administrative, economic, and military policies employed by the Crown in this territory during the dynastic union, and demonstrate how they were closely intertwined with the economic expansion of Spanish American colonial societies. Portuguese large-scale warfare in Ndongo was contemporary with Spanish’s own economic expansion in the Americas, and the vast number of slaves captured in West Africa supported Spanish American’s colonial societies. This dissertation also explores the financial and legal organization of the Iberian slave trade. It explores the different policies and strategies for capture and acquisition of African slaves in Angola, and its relationship with the financial mechanisms drawn in the metropolis by both Iberian Crowns. To conduct businesses on the territories on the edge of the empire, knowledge of the different colonial markets was crucial, and attainable only through the establishment of networks with local entrepreneurs or on the spot agents experienced with cross-cultural trade, who could oversee their operations. This research captures some of the commercial strategies and dynamics of local elites from Luanda participating on the slave trade, both from an official and informal nature, and intermingles their business operations and slave capture activates with distant credit operations between the metropolis or in America.