Gaius Julius Bassianus or Bassus, also known as Julius Bassianus (flourished second half of the 2nd century and first half of the 3rd century, died 217) was a Syrian High Priest of Arab descent from north Arabia. Bassianus was a high priest for the Temple of the Sun in Emesa, which was adored in a shape of a black stone. The Aramaean Sun God in Aramaic is El-Gebal. Bassianus was a member of the Royal family of Emesa (modern Homs, Syria). The Royal Family was a part of the local Syrian Aramaean aristocracy and was a client kingdom of the Roman Empire. The beginning of his priesthood is unknown but by 187, he was a high priest at Emesa. Bassianus was a son of a Julius and his paternal uncle was Julius Agrippa, who served as a Primipilaris (a former leading Centurion).
Future emperor Lucius Septimius Severus had visited Emesa, based on a promising horoscope that he would find his future wife in Syria. Bassianus introduced Severus to his two daughters. Bassianus' wife is unknown. His elder daughter Julia Maesa was married to a Syrian noble Gaius Julius Avitus Alexianus and they had two daughters Julia Soaemias Bassiana and Julia Avita Mamaea. His younger daughter Julia Domna was not married.
Severus and Domna, married not so long after. Domna bore Severus two sons, Lucius Septimius Bassianus (Caracalla, 4 April 188-8 April 217) and Publius Septimius Geta (7 March 189-19 December 211). Caracalla and Geta would become future Roman Emperors and heirs to their father.
Julia Maesa prevailed upon her grandson, the emperor Elagabalus to adopt another grandson, the son of Julia Avita Mamaea, who took the name Alexander Severus and eventually became emperor. Bassianus is a possible descendant of princess Drusilla of Mauretania and could be an ancestor to Syrian Queen Zenobia of Palmyra.