Gaius Julius Severus was a Tribune in Legio VI Ferrata, then and usually settled in Iudaea. He was the older son of Gaius Julius Severus, a Nobleman from Akmonia at Galatia, and paternal grandson of Artemidoros of the Trocmi, a Nobleman at Galatia (son of Amyntas, Tetrarch of the Trocmi, King of Galatia), and his wife a Princess of the Tectosagi (daughter of Amyntas, Tetrarch of the Tectosagi). His older brother was Gaius Julius Bassus, a Proconsul in Bithynia in 98. He was the father of (Gaius) Julius Quadratus, a Roman Cavalry Officer.