IN HIS WORK La Chevalerie, published in 1884 and aimed at a mass audience beyond the scholarly community, Léon Gautier, a graduate of the École nationale des Chartes, declared that

This judgment, by no means an isolated one in the religious literature of the nineteenth century and even in the first half of the twentieth until the Second Vatican Council, is a good summary of the deep feelings of legitimist Catholics, convinced that the medieval period was not just a rainbow of bright colours, but also a religious ideal to be followed. It provided an exemplary social model: that of an organic society unified under the benevolent supervision of a protective monarch, who, like St. Louis (King Louis IX), respected the rights of all his subjects, and a paternalist clergy, who, through charity, made sure no one was left by the wayside. This was a harmonious world on a European scale—Christendom—in which everyone had the place assigned them by providence, knowing nothing of the dire contemporary class struggles.

In our contribution, we look at how and why Catholic elites used the idealized Middle Ages in this way, brandishing it as a weapon against revolutionary modern times accused, by smashing the social unity of the Ancien Régime, of having left the individual alone and isolated against an all-powerful State. We will analyse this veritable Catholic crusade against the France stemming from the Revolution in four successive sequences:

• 1. The period of nostalgia for the Middle Ages reconstructed in the colours of Romanticism, from about 1830 to 1860.

• 2. The time of Frédéric Le Play, from 1860 to 1890, when the Middle Ages was reclaimed by the social science developed by this former mining engineer.