a1 Harvard University
The fifth-century mosaics of Santa Maria Maggiore in Rome represent the oldest surviving program of mosaic decoration in a Christian church. Its political context includes the steady drain of political authority and power to the Eastern empire from the early fourth century forward, the proscription of paganism at the end of the fourth century, and the massively disruptive Sack of Rome by Alaric in 410 CE. In the vacuum of political power in the West, the papacy under Sixtus III made a strong claim for a new basis of Roman power—the religious primacy of the city of Peter and Paul under papal leadership. The building and decoration of Santa Maria Maggiore played an important role in the consolidation and public announcement of papal power.