Dante Alighieri's Purgatorio, the second canticle of the Divine Comedy, completed around 1320, gave Purgatory its enduring shape. Where earlier tradition spoke only of a purifying fire, Dante drew a place: a single mountain rising from the sea at the antipodes of Jerusalem, formed, in his geography, by the earth that fled downward when Lucifer fell and hollowed out Hell beneath the northern hemisphere. Ante-Purgatory circles its base, holding the late repentant, the excommunicate and those who died a violent death without absolution, all of whom must wait before the climb even begins. Above that, seven terraces ring the mountain in ascending order, pride, envy, wrath, sloth, avarice, gluttony, lust, each purging one of the seven deadly sins through a penance that answers the sin in kind: the proud bent under stone, the envious with their eyes sewn shut, the gluttonous starved before fruit they cannot reach. At the summit stands the Earthly Paradise, the garden of Eden restored, where Dante meets Beatrice and the mountain's project completes, every soul who reaches the top is already clean and ascends to Heaven without further trial.
This topography became the culture's default image of Purgatory far beyond theology. Illustrators from Botticelli onward, through Gustave Dore's nineteenth century engravings and William Blake's watercolors, worked from Dante's mountain rather than from conciliar decree. The Council of Trent's own instruction to preachers, that the fires, the durations and the arithmetic of Purgatory should not be preached as settled, left exactly the imaginative space Dante's poem had already filled: readers picture the mountain, not the canons.