The third place -- Part One: The hereafter before Purgatory -- Ancient imaginings -- The fathers of Purgatory -- The early Middle Ages: doctrinal stagnation and the riot of imagination -- Part Two: The twelfth century: the birth of Purgatory -- The century of the great advance -- The fire of Purgatory -- "Locus Purgatorius": a place for purgation -- Purgatory between Sicily and Ireland -- The logic of Purgatory -- Part Three: The triumph of Purgatory -- The scholastic systematization -- Social victory: Purgatory and the cure of souls -- The poetic triumph: The Divina Commedia -- Why Purgatory?