Most students of history assume that the age of the "warlord popes" ended with the Renaissance, but, long after the victory of Catholic powers at the Battle of Lepanto in 1571, the Papacy continued to entangle itself in martial affairs. The Vatican participated in six major military campaigns between 1796 and 1870, flew the papal flag over a warship as late as 1878, and during the Second World War mobilized more than 2,000 of its own troops to defend the Pope. David Alvarez now opens up this little-known aspect of the Papacy in the first general history of the papal armed forces. His is the first book in English to provide a comprehensive chronicle of the modern Vatican's military and security forces from 1796, when the armies of revolutionary France invaded the Papal States, through the wars for unification, to the present-day deployment of modern weapons, technology, and skills to protect the Holy Father and the Vatican from terrorists and assassins. Most papal histories make little reference to military affairs, while the few that address them do so only in passing or focus narrowly on particular units or campaigns. Alvarez's history expands our understanding of the Papacy's military through the exceptional research he has done as the first American scholar to gain access to the archive of the Pontifical Swiss Guard and the modern military records in the Vatican Secret Archive. He is also the first historian of any nationality to use the records of the Vatican Gendarmeria. Alvarez chronicles the exploits of the Vatican's military leaders and soldiers in their campaigns and battles, focusing on how those units under the Pope's authority--including the Vatican navy--engaged in actual military operations. He also deals extensively with the Vatican Gendarmeria as well as the Pope's Noble Guards, Palatine Guards, and Swiss Guards, describing their distinctive responsibilities and revealing the competition and internal tensions that sometimes undermined the morale, preparedness, and cohesion of the Pope's guards. Filled with information that will surprise scholars of the Papacy and military historians alike, Alvarez's highly original work illuminates a shadowy corner of Vatican history and will fascinate all readers interested in the role of the church in the broader world.