SEMO SANCO. — Semo Sanchus Dius Fidius, an Italic deity of the Jupiter cycle whose name recalls the Semones of the Arval cult; b) the characteristic of sanctioning, i.e., guaranteeing oaths; and c) the epithet proper to Jupiter as guardian of oaths; cf. Σωκρ πίστω; and the Físsos Sancios of the Eugubine Tables.
S. S. had in Rome a temple on the eastern slope of the Quirinal Hill, hence called Sanqualis, just as Sanqualis was the name of the local gate of the Servian wall. The temple was dedicated in 446 B.C.; the dedication fell on June 5 (Ovid, Fasti, VI, 213). Two ritual peculiarities are known which well suit a deity of oaths: it had part of its roof open to the sky; inside it preserved some bronze disks (orbes aenei) symbolizing the solar disk and recalling the analogous urfeta (= orb) of the Umbrian ritual. Treaties were kept in the temple. In the garden adjoining the church of St. Sylvester on the Quirinal, inscriptions relating to the god were found. The most important (though of unknown provenance, discovered in 1879) bears the dedication “Semoni Sanco sancito deo Fidio” set up by the “decuria sacerdotum bidentialium” (CIL, VI, 30.994), a priestly college in charge of fulgural discipline and thus precisely entrusted with the custody of that god’s temple “qui foedera fulmine sancit” (Virgil, Aen., XII, 200).
The statue (found in the same locality as the base, now in the Vatican Museum, and representing an archaic type of Apollo) has no connection with the base. On the Tiber Island there was another sanctuary of the god, known for the mistaken attribution which Christian apologists (Justin, Apol., I, 26; Tertull., Apol., 13) made of it to Simon Magus, deceived by the dedicatory inscription.