seems to have carried the princess's sarcophagus". This is where the sarcophagus of Constantina, or perhaps the second one, would have rested. The ambulatory is barrel-vaulted and is 22.5 meters or 74 feet in diameter. The ambulatory has most of the surviving mosaics in the church. Larger arches mark the cardinal points in the mausoleum. The walls were probably covered in slabs of colourful marble, as was usual in imperial buildings. Santa Costanza was also to some extent a new type of building. It was different from earlier styles in that the roof, which would previously have been typically flat and made with wood, was instead designed as a dome and vault. Decoration Mosaics The mosaics of Santa Costanza are important examples of Early Christian art, and even rarer examples of secular palace ceiling mosaics. The apses, central dome, and ambulatory all had mosaic decoration, though that in the dome no longer survives. Mosaics in the apses In the ambulatory wall there are two shallow apses, each with a mosaic showing Christ as the Pantocrator, the earliest surviving examples of this depiction; they probably date to the 5th or 7th century, though there has been much discussion of this. Like many mosaics of the period, both have suffered from restoration and both show elements of Roman imperial imagery, representing early examples of the conflation of this with Christian art. A mosaic with two women wearing white, reported as being behind the sarcophagus in the Renaissance, has now gone and was never drawn. One of the apses shows a traditio legis: Christ is shown with Saints Peter and Paul giving Peter the scroll representing law, with the inscription, "DOMINUS PACEM DAT," or "The Lord is giving Peace." A few sheep represent his role as shepherd governing and leading his flock. Christ is clothed in golden robes, suggesting his power and supremacy. He is shown rising above paradise, which further shows his dominance over both heaven and earth. In the second apse, Christ appears somewhat more simply but still as supremely powerful. His robes are not quite as rich as in the other apse, but still suggest power. He wears a simple tunic but it is purple and gold. This suggests not only holy power, but human power given that purple is the color of royalty and the gold stripes suggestion a connection to the Roman emperors. Peter also approaches Christ in