The outline of the nineteenth-century encounter between Roman Catholicism and liberalism is familiar to readers of almost any modern history text.

The drama begins when the French Revolution tries first to retailor the church to a revolutionary pattern and then, having fallen short in the effort, attempts to replace Christianity altogether. The church casts its lot with counter-revolution. During the restoration the papacy renews and reinforces the bonds between the throne and altar with a series of concordats and with support for Metternich's Holy Alliance.

For the rest of the century this post-revolutionary settlement is repeatedly challenged and gradually dismantled – by revolutionary forces in 1830 and 1848; by the loss of the papal states to a unified Italy in 1870; by Bismarck's 1873–78 Kulturkampf against the church in a unified Germany; by the French Third Republic's turn to Gambetta's anti-clericalism in 1877 and, after the debacle of the Dreyfus Affair, by the harsh separation of church and state in 1905; by the seemingly inexorable rise of an anti-religious socialism among the working class and an anti-religious science among the educated. At the century's end, the pope has sentenced himself to becoming a “prisoner in the Vatican” and the church is forced to the margins of cultural and political life.

Meanwhile, there has been a parallel series of challenges from within the church itself. First there is the meteoric rise and fall of Félicité de Lamennais and his dramatic appeal to replace the alliance of throne and altar with an alliance between people and altar based on universal suffrage and freedom of religion and opinion.