At the beginning of the period selected by Giuliana Chamedes for her study of international Catholicism during Europe’s age of catastrophe, the Pope was sulking in his tent as the self-styled ‘prisoner of the Vatican’, just as his predecessors had done ever since the Risorgimento deprived the papacy of its command over the inhabitants of Rome and central Italy. A French invasion force had put paid to the short-lived Roman Republic of 1848, enabling the Vatican to drive Rome’s Jewish population back into the ghetto and restoring the authority of the local Inquisition. This time, however, there was to be no counter-revolutionary knight in shining armour riding to the Pope’s salvation. The leaders of the Catholic Church denounced the new Italian state for trespassing upon their sacred rights, directed their flock to boycott its structures, and withdrew to a rump of territory around St Peter’s. A temporal power that reached back to late antiquity, having survived the ingresses of Visigoths and Lombards, Arabs and Normans on Italian soil, now appeared to have met its nemesis in the form of Garibaldi and Cavour.

The term ‘prisoner of the Vatican’, while certainly memorable, could be said to take a certain poetic licence, as a rogue member of the Church’s spiritual infantry noted in 1887. Father Eugene Sheehy was an Irish priest and an enthusiastic supporter of the Land League, whose Plan of Campaign the Vatican had vigorously condemned, as a gesture of solidarity towards the landowning class in general and the British government in particular. Sheehy repaid the favour with a famous sermon on the occasion of ‘Peter’s Pence’, the annual collection for the Bishop of Rome.

He began by noting that his parishioners must have heard the Pope referred to as the ‘prisoner of the Vatican’, which was liable to evoke certain images in their minds, of ‘friends and relations who are prisoners at this moment for having taken part in the Plan of Campaign, a morally lawful movement which the British misled the Pope into condemning.’ Sheehy had recently visited his own brother, a nationalist mp, in Tullamore Jail:

He was naked in his cell, in this freezing weather, because he rightly refuses to wear the prison clothes, being no criminal. You may have pictured our Holy Father as enduring some such conditions. Let me relieve your anxieties. I visited the Pope in Rome last year. He lives in a splendid and spacious palace in which he is free to move around. He has whatever he likes to eat and drink. He has many servants. In no way does the Vatican resemble Tullamore Jail.

Sheehy concluded with a terse injunction: ‘You are not wealthy people. But you are to contribute whatever you feel you can afford to the support of the “prisoner of the Vatican”’. As Sheehy’s grand-nephew Conor Cruise O’Brien gleefully recalled, ‘not one penny reached the Vatican that year from the Parish of Bruree.’

Despite Sheehy’s best efforts, the Vatican still disposed of considerable resources a generation later, if it had a mind to use them. The narrative supplied by Chamedes carefully documents its sustained efforts to do so in a Europe rocked by war and revolution, as successive Popes emerged from their amply gilded cage in Rome with two interlocking goals in mind: to secure the position of the Church in a time of turmoil through concordats with secular authorities, and to deploy Catholic power in support of the political forces—reactionary, illiberal, authoritarian—that the Vatican found most congenial. The violence that was deployed in support of those forces, often with the explicit sanction of the Church, amply justifies the author’s choice of the term ‘crusade’ as an organizing rubric.

Chamedes begins her account in the latter stages of the First World War, under the papacy of Benedict XV (1914–22). Vatican diplomacy had tilted in favour of the Central Powers, thanks not least to the relationship between Rome and a coterie of German Catholic politicians grouped around Matthias Erzberger—Erzberger’s suggestion that the war ‘offers the opportunity for the Pope to reclaim full freedom and independence’ after the humiliation of 1870 supplies the epigraph for the opening chapter. Vatican officials lobbied against us intervention on the side of the Allies. When these efforts proved unavailing, Benedict XV issued a seven-point peace plan in August 1917, hoping to ‘respond to the specter of a Wilsonian postwar settlement and to steal the fire of the socialists’. (Kaiser Wilhelm II, who had been consulted on the plan, found the latter objective especially commendable.)