At Purgatory’s gate in *Purgatorio*, Dante climbs three steps before the angel admits him. The steps lead to the entrance of Purgatory proper, beyond the Ante-Purgatory where the late-repentant wait.
Each step has a different appearance. The lowest is polished white marble that reflects Dante’s image; the middle is dark, rough stone cracked in the shape of a cross; and the upper step is vivid red porphyry. An angelic gatekeeper sits above them on an adamantine threshold.
The three steps are commonly read as stages of repentance or penance. Interpretations vary, but they are often connected with self-examination, contrition, and the satisfaction or confession required before spiritual renewal. The symbolism explains why the scene is more than a literal staircase.
A common mix-up is with the seven terraces of Purgatory, which Dante ascends after entering. The angel also marks seven P’s on his forehead, one for each deadly sin, and removes them progressively as Dante climbs the mountain.