One of the most powerful women of the Byzantine world was the daughter and granddaughter of Roman emperors and sister of one ruler of the Western Roman Empire and widow of another. Captured by the Visigoths during the sack of Rome in 410, she married King Athaulf, moved with his barbarian hordes to Barcelona, was traded back to the Romans for grain when Athaulf was murdered, and then married co-emperor Constantius, with whom she had a son, Valentinian III. When Constantius died and Valentinian became emperor at the age of six, Galla acted as regent and in that capacity ruled the Western world for 12 years. Though she’s most likely buried in Rome, her mausoleum here is crowned with a dome decorated with mosaics, vivid with hues of peacock blue, moss green, Roman gold, eggplant, and burnt orange and especially moving for their simplicity and spirituality. Doves drink from fountains, as the faithful are nourished by God; a purple-robed Christ is surrounded by lambs, as the Heavenly king is surrounded by the faithful; and 570 tiny gold stars, suggesting life eternal, twinkle in the cupola. Soft light filtered by alabaster imparts the surroundings with an other-worldly luminosity.