The building was formerly the oratory of the Church of the Holy Cross and now contains three sarcophagi. The largest was thought to contain the remains of Galla Placidia (died 450), daughter of the Roman Emperor Theodosius I. Her embalmed body was reportedly deposited there in a sitting position, clothed with the imperial mantle. In 1577, however, the contents of the sarcophagus were accidentally burned. The sarcophagus to the right is attributed to Galla's son, Emperor Valentinian III, or to her brother, Emperor Honorius. The one on the left is attributed to her husband, Emperor Constantius III.
It is surmised that the structure was built by Galla Placidia, who was a well-known patron of the arts, to be used as a mausoleum for her and her family. There seems to be no evidence to prove or disprove Galla’s connection to the building. The mausoleum was once connected to the narthex of Santa Croce, the church for the imperial palace, built in 417 but now in ruins. Santa Croce was one of the first buildings commissioned by Galla. The floor has been raised by five feet since the fifth century in order to remain above the rising water along the upper Adriatic coast.
|The ceiling is all sumptuously decorated with fine mosaic work|