Two of the most striking developments in the modern history of global Christianity have been the respective strengths of Catholic Christianity in Central and Latin America and of Protestant and Pentecostal Christianity in mostly sub-Saharan Africa. The aim of this chapter is to shed some light on these important stories by focusing on two early modern, imperial case studies, one from the Spanish conquest of New Spain and another from the British colonial project in West Africa, specifically Sierra Leone. Moreover, to what extent does the theoretical model of nuclei (the inner core of religious traditions), nodes (points of connection and exchange), and networks (transnational flows of people, ideas, and artifacts) help us understand better the various processes that produced such significant consequences for the global transmission of Christianity in the early modern and modern world?