The low-relief sculpture fragment of Mercury in an archaizing style dates to the reign of the emperor Hadrian (117-38 CE.) Its presence on the portico of Sessa’s cathedral, together with an inscription reading “MERC”once visible in the interior, gave rise to a tradition that the cathedral was built over the ruins of a temple of Mercury. While excavations on the site have not produced evidence supporting this claim, it is likely that some spoliate material used in the construction of the cathedral came from a temple dedicated to Mercury.
Its placement beside the thirteenth-century sculptural cycle illustrating scenes from the life of St. Peter creates an interesting juxtaposition of two very different episodes of historicism. The sculptor of the Mercury panel carefully emulates the stiff figural poses and stylized drapery treatment of Archaic Greek art; at the time of its creation, older styles were favored by the Roman market. In the case of the Petrine sculptural cycle, the referent is Rome, though here there is another sort of relationship between the work and its visual influences. For the artisans who carved the cycle, Rome was a memory, distant, though refreshed through the continued presence of ruins and spolia, and viewed through a prism of centuries of iterations and interpretations.