The reliquary is composed of elements from at least three eras: the hexagonal base of the 14th century, with perimeter inscription in Gothic characters; the elegantly decorated shaft with a discernible 15th century imprint; and the cylindrical jar topped by a small dome, perhaps from the 16th century. The feet, the small column and the dome may in fact be attributed to a restoration project of the first quarter of the 18th century, by Bernardo Holzmann.

The case at the bottom contains six relics, one on each side, visible through display windows, while the relic of Saint Simeon Stylites is housed in the jar at top.

The inscription surrounding the base of the lower reliquary reports that Charlemagne, King of the Franks, donated the relics collected by Archbishop Turpin, in the year 805, to Florence; in 1398 they were placed in this hexagonal box. According to other sources, the relic of Saint Simeon was donated to the Guild of Calimala in 1394 by the Venetian noblewoman Nicoletta Grioni, who had imported them from the Byzantine imperial court; Nicoletta was the widow of the Florentine nobleman Antonio di Pietro Torrigiani, whose father was for some years the secretary of the Eastern Emperor, Giovanni VI Cantacuzeno.