A chapel at a great depth below the church, is shown as that in which St. Urban baptized and celebrated mass. A curious fresco here represents the Virgin between St. Urban and St. John. Around the upper part of the interior are a much injured series of frescoes, comprising--the life of Christ from the Annunciation to the descent into Hades,--and the life of St. Cecilia and her husband Valerian, ending in the burial of Cecilia by Pope Urban in the Catacombs of Calixtus, and the story of the martyred Urban I. In the picture of the Crucifixion, the thieves have their names, "Calpurnius and Longinus." The frescoes were altered in the seventeenth century to suit the views of the Roman Church, keys being placed in the hand of Peter, &c. Sets of drawings taken _before_ and _after_ the alterations, are preserved in the Barberini Library, and curiously show the difference. A winding path leads from S. Urbano into the valley. Here, beside the Almo rivulet, is a ruined Nymphæum containing a mutilated statue of a river-god, which was called "the Grotto of Egeria," till a few years ago, when the discovery of the true site of the Porta Capena fixed that of the grotto within the walls. The fine grove of old ilex-trees on the hillside, was at the same time pointed out as the sacred grove of Egeria. "Egeria! sweet creation of some heart Which found no mortal resting-place so fair As thine ideal breast; whate'er thou art Or wert,--a young Aurora of the air, The nympholepsy of some fond despair; Or, it might be, a beauty of the earth, Who found a more than common votary there Too much adoring; whatsoe'er thy birth, Thou wert a beautiful thought, and softly bodied forth. "The mosses of thy fountain still are sprinkled With thine Elysian water-drops; the face Of thy cave-guarded spring, with years unwrinkled, Reflects the meek-eyed genius of the place, Whose green, wild margin now no more erase Art's works; nor must the delicate waters sleep, Prisoned in marble, bubbling from the base Of the cleft statue, with a gentle leap The rill runs o'er, and round, fern, flowers, and ivy, creep, "Fantastically tangled; the green hills Are clothed with early blossoms, through the grass The quick-eyed lizard rustles, and the bills Of summer-birds sing welcome as ye pass; Flowers fresh in hue, and many in their class, Implore the pausing step, and with their dyes Dance in the soft breeze in a fairy mass; The sweetness of the violet's deep blue eyes, Kiss'd by the breath of heaven, seems coloured by its skies." _Byron, Childe Harold._ It is now known that this nymphæum and the valley in which it stands belonged to the suburban villa called Triopio, of Herodes Atticus, whose romantic story is handed down to us through two Greek inscriptions in the possession of the Borghese family, and is further illustrated by the writings of Filostratus and Pausanias.