Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[75] NOW when the king's brother, Monobazus, and his other kindred, saw how Izates, by his piety to God, was become greatly esteemed by all men, they also had a desire to leave the religion of their country, and to embrace the customs of the Jews; but that act of theirs was discovered by Izates's subjects. Whereupon the grandees were much displeased, and could not contain their anger at them; but had an intention, when they should find a proper opportunity, to inflict a punishment upon them. Accordingly, they wrote to Abia, king of the Arabians, and promised him great sums of money, if he would make an expedition against their king; and they further promised him, that, on the first onset, they would desert their king, because they were desirous to punish him, by reason of the hatred he had to their religious worship; then they obliged themselves, by oaths, to be faithful to each other, and desired that he would make haste in this design. The king of Arabia complied with their desires, and brought a great army into the field, and marched against Izates; and, in the beginning of the first onset, and before they came to a close fight, those Handees, as if they had a panic terror upon them, all deserted Izates, as they had agreed to do, and, turning their backs upon their enemies, ran away. Yet was not Izates dismayed at this; but when he understood that the grandees had betrayed him, he also retired into his camp, and made inquiry into the matter; and as soon as he knew who they were that made this conspiracy with the king of Arabia, he cut off those that were found guilty; and renewing the fight on the next day, he slew the greatest part of his enemies, and forced all the rest to betake themselves to flight. He also pursued their king, and drove him into a fortress called Arsamus, and following on the siege vigorously, he took that fortress. And when he had plundered it of all the prey that was in it, which was not small, he returned to Adiabene; yet did not he take Abia alive, because, when he found himself encompassed on every side, he slew himself.