In the sixteenth and seventeenth centuries, Rome was an aged but still vigorous power while Spain was a rising giant on track toward becoming the world's most powerful and first truly global empire. This book tells the fascinating story of the meeting of these two great empires at a critical moment in European history. Thomas Dandelet explores for the first time the close relationship between the Spanish Empire and Papal Rome that developed in the dynamic period of the Italian Renaissance and the Spanish Golden Age. The author examines on the one hand the role the Spanish Empire played in shaping Roman politics, economics, culture, society, and religion and on the other the role the papacy played in Spanish imperial politics and the development of Spanish absolutism and monarchical power. Reconstructing the large Spanish community in Rome during this period, the book reveals the strategies used by the Spanish monarchs and their agents that successfully brought Rome and the papacy under their control. Spanish ambassadors, courtiers, and merchants in Rome carried out a subtle but effective conquest by means of a distinctive "informal" imperialism, which relied largely on patronage politics. As Spain's power grew, Rome enjoyed enormous gains as well, and the close relations they developed became a powerful influence on the political, social, economic, and religious life not only of the Iberian and Italian peninsulas but also of Catholic Reformation Europe as a whole.