Gaius Arrius Domitianus

Gaius Arrius Domitianus  is securely attested only in Scotland, at Newstead/Trimontium (Scottish Borders), where he turns up four times as a centurion of Legio XX Valeria Victrix—all as altar dedicant:

RIB 2123 – altar to Jupiter Optimus Maximus, found 1905 in the fort HQ well; now NMS Edinburgh.

RIB 2122 – altar to Diana Regina, found 1909 in the east annexe ditch; now NMS.

RIB 2124 – altar to Silvanus, Trimontium; now NMS (also indexed in EDH HD071258).

RIB 2125 – fragmentary altar (deity lost), text still shows his name and rank; now NMS.

RIB’s person index collates these as a single individual and notes the view that he also commanded a vexillation of Legio XX and the ala Vocontiorum during the early Antonine occupation at Newstead.

Outside Scotland / elsewhere in the Empire

I can’t find any secure continental or extra-British inscription naming him. EDH lists the Silvanus stone from Trimontium and cross-links back to RIB; there are no other sites for this person. In short: his epigraphic footprint is Trimontium-only.

Roman naming and what’s likely:

Gaius (C.) – a very common praenomen.

Arrius – a nomen (family name), known from several Italian and provincial families; e.g. the Arrii were a plebeian gens at Rome, with branches in Italy and also in the provinces after enfranchisement.

Domitanius – a cognomen that looks derived from Domitianus (perhaps from the imperial name Domitianus, or from domitus “tamed”). It would usually indicate either manumission under, or clientage to, someone of the Domitius/Domitianus family, or simply a fashion-name after the emperor Domitian.