Gaius Julius Erucius Clarus Vibianus
Vibianus came from an Italian family or from one of the Western provinces. He was the son of Gaius Erucius Clarus, consul in AD 170. He came from the powerful equestrian family of the Erucii. His grandfather, Sextus Erucius Clarus, was consul in AD 146, and before that City Prefect of Rome. His great-grandfather, who was consul suffectus in AD 117, was the brother (or perhaps half-brother) of Gaius Septicius Clarus.