The form of the domed reliquary resembles a crossed-dome church. The diverse ornamentation blanketing the surface of the architectural framework turns the building inside out, so to speak, bringing the decoration typical of a church interior to the outside. The reliefs on the ends of each arm of the cross show the Holy Family, the journey of the Magi, the Crucifixion, and the women at the tomb. Prophets holding banderoles inscribed with their prophecies fill the remaining arcades. As representatives of the old covenant they foreshadow the apostles, who, as witnesses to the new covenant, appear enthroned around Christ on the drum of the dome. In 1482 the reliquary housed the head of St. Gregory of Nazianzus. Among other indications, the absence of pictorial or epigraphic evidence identifying it as a reliquary has recently lead to the assumption that this piece, as well as a similar one in the Victoria and Albert Museum in London, originally served as a tabernacle to store the consecrated host.