Ananias of Adiabene (/ˌænəˈnaɪəs/; c. 15 BCE – c. 30 CE) was a Jewish merchant and mendicant proselytizer, probably of Hellenistic origin, who, in the opening years of the common era, was prominent at the court of Abinergaos I (Abennerig), king of Characene. He was instrumental in the conversion to Judaism of numerous native and foreign inhabitants of Charax Spasinu. This city, the capital of Characene, was situated at the confluence of the two arms of the Tigris and was at the time a great mercantile center.
Among Ananias' most prominent converts were several women of high position at the court, particularly the princess Symacho, the king's daughter. This princess married Izates bar Monobaz, a young prince who had been sent to Abennerig's court by his parents, Monobaz I and Helena, the rulers of Adiabene. Through his wife, Izates' attention was directed to Ananias, with whom he formed an acquaintance that eventually ripened into a strong attachment. Around the year 18 CE, Ananias won the prince over to the Jewish faith. Moreover, Izates was named as successor to the throne by Monobaz, who, in so doing, passed over his elder sons. Upon his accession (about 22), Izates, in order to show his genuine attachment to the new religion, declared his determination to undergo the rite of circumcision. Helena opposed this, fearing that the adoption of foreign ceremonies might arouse against the young king the indignation of his pagan subjects. Ananias, who had come to Adiabene with Izates, supported Helena's contention, arguing that such a step on the part of the king would endanger the life of his Jewish instructor, and, further, that circumcision was not vital to the fulfilment of the Jewish religion and the worship of God.