Publius Virdius Bassus belonged to the equestrian family of the Virdii (cf. IGBulg 1174). He is attested in a dedication to Asclepius from the sanctuary near the village of Batkun (IGBulg V.5483) as thracarches. He appears to have been one of the two sons of Publius Virdius Iulianus, “father of two military tribunes and himself formerly in the army” (πατέρα δύο χειλιάρχων καὶ αὐτὸν ἀπὸ στρατείας) according to an honorary inscription from Philippopolis (AE 2005, 1382).