This dissertation traces the foundations of Spanish imperial rule in the Philippines during the late 16th century. It suggests that indigenous rulers were a key component of the Spanish colonial enterprise, acting as intermediaries that facilitated the government, the mobilization of resources, and the Christianization of the archipelago. In three chapters, this research explains how the local and global transformations that framed European colonial expansion in Asia and the Americas allowed the incorporation of Filipino principales as brokers of Spanish colonial dominion. On a global scale, the changing colonial approaches of early modern European empires, the ideas of Spanish theologians about indigenous rights, the imperial competition for the riches of Asia, the colonization of the Americas, and the political union of Castile and Portugal in 1581 shaped the incorporation of native Filipinos into the Spanish realm. Simultaneously, at the local level, the potential gains and benefits that native elites perceived by accepting Spanish rule and Christianity, their interpretation and adaptation of Spanish legal culture, and the endless struggle between the different colonial authorities of Manila also defined the gradual integration of native Filipinos as vassals of the Crown.