Istacidia gens
The gens Istacidia was an obscure Roman family at Pompeii. No members of this gens are mentioned by ancient writers, but a number are known from inscriptions. Numerius Istacidius Cilix was one of the municipal duumvirs of Pompeii around the beginning of the first century. The Istacidii were apparently the residents of the famous "Villa of the Mysteries", and a large sepulchre found along the bay road contains several tombs for members of this family. Origin. The Istacidii were most likely of Campanian origin, as all of the inscriptions of this family are from Pompeii, and one of  them bore the surname "Campanus", one of a class of surnames derived from place names, and usually indicating a person's place of origin. Praenomina. The main praenomina of the Istacidii were "Numerius" and "Lucius", accounting for all of the Istacidii whose praenomina are known, except for one instance of "Marcus", found in a filiation. "Lucius" and "Marcus" were among the most common of all Roman names at all periods of history, while "Numerius" was much more distinctive; while not actually rare, it was typical in families of Oscan origin. Branches and cognomina. The inscriptions of the Istacidii at Pompeii  suggest that they constituted a single family, together with their freedmen. Several inscriptions of this gens do not include a cognomen, and none of the surnames of this gens appear to have been hereditary. "Cilix", a surname originally applied to someone from Cilicia, gives the appearance of the type of name belonging to a freedman, and indicating his place of origin; but as it belonged to one of the "duumviri", it may instead have stemmed from his trading connections.