From the earliest centuries of Christianity, the faithful believed, albeit somewhat vaguely, in the possibility of redeeming certain sins after death. But in the dualistic system of the afterlife, between Hell and Paradise, there was no place for the fulfillment of these intermediate punishments. It was not until the end of the 12th century that the word "purgatory" appeared and that Purgatory became a "third place" of the afterlife, a new geography of the other world. Purgatory is part of a mental and social revolution that replaced dualistic systems with systems that introduced the notion of intermediation and that accounted for spiritual life; it is also the triumph of individual judgment in the new relationships between the living and the dead.

A classic and indispensable work of medieval studies, and of cultural and religious history, this brilliant research traces the vicissitudes of the birth of Purgatory from Antiquity to Dante's Divine Comedy, analyzing one of the great episodes in the spiritual and social history of the West.