Coppa provides the first full-length study of Giacomo Antonelli, friend and advisor to Pope Pius IX (Pio Nono) and his Secretary of State and chief minister from 1849 to 1876. Based on the documents of the secret Vatican Archives, and neglected family papers in the State Archive in Rome, the book gives an important reevaluation of this key diplomatic figure, separating the man from the myth and delving into his character and policies.

The book examines both the personality and policies of the Cardinal, who was seen to be the Pope's Richelieu and Mazarin combined. Confronting the polemical literature which has charged him with sexual misconduct and venality, the study examines his early formation and career, the inspiration for his European policies, his relationship to Pio Nono, and the part he played in the Counter-Risorgimento and the Papal reaction. By improving our understanding of Papal, Italian, and European developments during these crucial decades, this study provides new insights into Rome's fortress mentality and its rejection of the main currents that were transforming western life— currents that influenced not only the Catholic Church but European society as a whole.