The angels up return'd with equal flight." After conversing with several friends whom he meets here, Dante falls asleep and is carried thus unconscious by Lucia (symbol of divine grace) to the gate of purgatory proper. When he awakes the sun is two hours high. Three steps lead to the gate, one dark and broken, symbol of a "broken and a contrite heart"; one of smooth, white marble, symbol of confession; and one purple, repentance. On the threshold of diamond (the immovable foundation of Holy Church) sits an angel with a sword and two keys; with the former he cuts seven P's on Dante's forehead (the Latin word for sin, _peccatum_), and with the latter he opens the gate, which as it swings open sends forth a sound of heavenly music: "Attentively I turned, Listening the thunder that first issued forth; And 'We praise thee, O God,' methought I heard, In accents blended with sweet melody. The strains came o'er mine ear, e'en as the sound Of choral voices, that in solemn chant With organ mingle, and, now high and clear Come swelling, now float indistinct away." In Terrace I. are punished the proud, crushed beneath enormous weights. On the side of the mountain wall are sculptured wonderful bas-reliefs, representing examples of humility; especially famous is the one which tells the story of Trajan's justice, a story which led Pope Gregory to make a prayer to God, who granted it, for the release of the pagan emperor's soul from hell: "There, was storied on the rock The exalted glory of the Roman prince, Whose mighty worth moved Gregory to earn His mighty conquest, Trajan the Emperor. A widow at his bridle stood, attired In tears and mourning. Round about them trooped Full throng of knights; and overhead in gold The eagles floated, struggling with the wind. The wretch appeared amid all these to say: 'Grant vengeance, Sire! for, woe beshrew this heart, My son is murdered.' He replying seemed: 'Wait now till I return.' And she, as one Made hasty by her grief: 'O Sire! if thou Dost not return?'--'Where I am, who then is, May right thee.'--'What to thee is other's good, If thou neglect thy own?'--'Now comfort thee;' At length he answers. 'It beseemeth well My duty be perform'd, ere I move hence: So justice wills; and pity bids me stay.' "He whose ken nothing new surveys, produced That visible speaking, new to us and strange, The like not found on earth. Fondly I gazed Upon those patterns of meek humbleness, Shapes yet more precious for their artist's sake." Farther on in the same terrace they see similar sculptures representing examples of punished pride, such as the fall of Lucifer, and the destruction of Niobe. In each of the following terraces these examples of sin and the opposite virtue are given, represented, however, by various means.