Fifteen hundred years ago, the emperor of Rome built a tomb for his beloved sister. The small building was designed in the shape of a cross with a vaulted ceiling covered with mosaics of swirling stars in an indigo sky. The focal point of the mosaic ceiling was a depiction of Jesus as a shepherd surrounded by sheep in a green paradise.

The mausoleum of Galla Placidia still stands in Ravenna, Italy, and has been called by scholars "the earliest and best preserved of all mosaic monuments" and one of the "most artistically perfect."

But visitors who have admired the mosaic in travel books and on postcards will be disappointed when they enter the mausoleum. The structure has only tiny windows, and what light does enter is usually blocked by a mass of tourists. The "most artistically perfect" mosaic monument, the inspiring vision of the Good Shepherd in a starry paradise, is hidden behind a veil of darkness.

But those who are patient, who endure the musty darkness ...