For Sturzo, the story of modern Catholicism is of a Church brought to its senses by being brought to its knees. The Church learns from being on the losing side, and what it learns is the necessary reciprocity of religious freedom. If the Church demands them for herself she must "suppose that such liberties are general for all". Yet is Sturzo's narrative too neat? Is the shift from the descriptive — what did happen — to the normative — what should have happened — too easy? Or does he get the story right?

The historical period Sturzo starts with, when the Church "had been against the introduction of political liberties", is the Bourbon Restoration. After the paroxysms of the French Revolution and the Napoleonic Wars, the Great Powers attempted to turn the clock back and reestablish the theocratic union of throne and altar. It was a doomed project, but one attempted nonetheless. In France, no sooner was the church reinstated to its unassailable position than it clamped down on religious freedom for non-adherents. In 1818 Protestants who refused to decorate their houses for processions of the Blessed Sacrament were prosecuted.

Meanwhile, in Italy religious freedom was even more grossly restricted. "There is no clearer way to discover the popes' attitudes and policies towards the Jews," remarks historian David Kertzer, "than seeing how the popes dealt with them when they had the power to do what they liked." The power to do what they liked was restored to the popes with the return of their lands in 1815. To avoid, as an internal Inquisition report put it, "the danger of the perversion of the Catholic faithful", the popes shamefully set about segregating Jews and Christians. Jews were forced into overcrowded, disease-ridden ghettos and banned from owning property outside them. In Rome they were forced to listen to sermons. When this persecution was questioned, Pope Gregory XVI retorted: "Disorders such as [Jews settling among Christians], while they may be illegally tolerated in secular states, cannot be tolerated in the Ecclesiastical state." A pure theocracy meant no place for religious liberty.

Yet while the Church opposed religious freedom in countries where it held sway, in other European countries it was Catholics who found themselves the losers. In 1800, Britain's union with Ireland massively inflated the nation's Catholic population, rendering increasingly intolerable the injustice of the exclusion of Catholics from the political process. Across the channel, when the Dutch monarch William I absorbed Belgium into Holland in 1815, Calvinists seized control of education, to the chagrin of Catholics. Under Russian rule the Catholic Church in Poland was denied self-government.

This contradiction did not escape notice, provoking a powerful internal challenge to the Church. It came from a French Catholic priest, Félicité de Lamennais, and the movement he founded from the 1820s onwards. Vexed by what he did not hesitate to call "the murder of Poland, the dismemberment of Belgium and the conduct of governments which call themselves liberal", Lamennais called on all Catholic nations to unite behind the cause of religious freedom "and the political liberties which are inseparable from them". Why did this task fall above all to Catholics? Because, Lamennais declared, "they have greater need of it than all others". He looked out across Europe and saw in how many places the losers were Catholics.