The primitive sanctuary was transformed into a hall oriented NE/SW, measuring 15.50 meters in length and 7.12 meters in width, ending with a large apse and featuring, on the upper level, a gallery parallel to the northwest perimeter wall, connected by an opening. The basilica is entirely clad in irregular striped masonry, with significant wall restoration work carried out during the 19th-century renovations by Father Marchi.
This scholar, analyzing the architectural features of the monument (Marchi, cited in bibliography, 191-199; plate XXXVIII), believed he could identify parts of an ancient nymphaeum repurposed by Christians, particularly in the series of niches that characterize the upper part of the side walls. However, it is now thought that these niches served rather as hollow buttresses to counteract soil pressure (Spera, cited in bibliography).
Moreover, the building cuts through the loculi of the galleries behind the apse and was therefore attributed by R. Krautheimer to the intervention of Pope Damasus. A reading of the architectural-structural layout, supported by literary sources, has instead suggested (Spera, cited in bibliography) that the martyrial building dates to the pontificate of Pelagius II (579–590), who likely carried out a significant expansion of the space *ad corpus*, demolishing the original structures and constructing the basilica, which partially emerged from ground level. As noted by the author of *De Locis* (Valentini-Zucchetti II, 117), the basilica was visible to visitors approaching the complex from the southeast (a finding corroborated by the discovery of a drainage mechanism during 1970s excavations: U.M. Fasola, *‘Lavori nelle catacombe’*, RACr 54 (1978), 10).
The restorations by Adrian I (772–795), mentioned by the author of the *Liber Pontificalis* (Duchesne, *Lib. Pont.* I, 509), who states that the pope *”basilicam…mirae magnitudinis innovavit”* (“renewed the basilica…of wondrous size”), are particularly evident in the perimeter walls, heavily restored during this phase.
**Description:** tomb/body
**Type:** Object of veneration not classifiable as an image or relic
**Collection of ex-votos:** Data unavailable
The earliest attestation of the cult of Hermes is found in the *Depositio Martyrum* of the Chronographer of 354, which records the celebration of his *dies natalis* on August 28. Einhard reports the translation of the relics to Gregory IV (827–844), who supposedly placed them in the recently restored Church of San Marco. While this translation is rather doubtful, the presence of a monastery likely ensured continuous visitation to the sanctuary, where, in the 12th century, a chapel was created using a section of the upper part of the basilica.
Connected to the foundation legend, echoed also in the martyr’s *passio* (*Acta Santorum*, May, I, Paris 1866, pp. 375–378), is the theme developed in the verses of the Damasan inscription, which presents the martyr as hailing from Greece and becoming a Roman citizen through the blood of martyrdom.
At an unspecified time, likely in the early Middle Ages, a monastic structure was added to the Sanctuary of Hermes. While the attribution to this site of the *Eugenius praepositus mo(nasterii) s(an)c(t)i Hermetis*, buried at San Saba in the 6th century (*ILCV* 1660; see A. Bacci, *‘Di alcune iscrizioni sepolcrali dell’oratorio di S. Silvia in S.Saba’*, *Nuovo Bullettino di Archeologia Cristiana* 13 (1907), 30–38), remains hypothetical, clearer evidence of the monastery’s existence appears in the *Catalogo di Torino*, which states that *”ecclesia Sti Hermetis extra muros non habet servitorem”* (Valentini–Zucchetti IV, 293; Ferrari, *Monasteries*, 152–155; L. Pani Ermini, *‘Testimonianze archeologiche di monasteri a Roma nell’Alto Medioevo’*, *ArchRomPatr*, 104 (1981), 20).
Via Salaria, Rome, Italy
