This article helps place Luisa Mangoni's "In partibus infidelium. Don Giuseppe De Luca: il mondo cattolico e la cultura italiana del Novecento" (Einaudi, 1989) on the broader path of the author's research. Standing at the centre of the author's investigation was her measured critical reconstruction of the particular project of Catholic Restoration of Italy promoted by De Luca in the season ushered in by the 1929 Concordat between the Holy See and the Kingdom of Italy during the fascist regime. This project was characterized by the centrality of "piety" as an element capable of satisfying popular devotion, the Magisterium of the Roman Catholic Church, and a culture with broad vision at the service of Roman Catholicism. The article also offers some thoughts on issues and problems in Mangoni's book, some of which were then further developed by historians: the relationship between De Luca and modernists; his opposition to the idealists; and the attitudes he held after World War II.