Regarding her marriage/ betrothal with [Gaius Julius Archelaus Antiochus Epiphanes Gaius Julius Archelaus Antiochus Epiphanes of Commagene] (b circa 38 to Antiochus IV Epiphanes, King of Commagene and Iotape Philadelphus)
which both Wikipedia & Wagner, Sir Anthony Richard; ‘Pedigree and Progress: Essays in the Genealogical Interpretation of History’ – says resulted in the birth of a daughter: Berenike of Commagene (b after 50), I can find the following '''contradictory''' sources on the net:
*>“Epiphanes was betrothed in 43/44 to the princess Drusilla, who was a daughter of Judean King Agrippa I. Agrippa thought that Epiphanes would embrace the religion Judaism and Jewish customs. However, Epiphanes never married Drusilla because he refused to adopt the customs and religion of the Jews. The marriage between Epiphanes and Drusilla had not been contracted on the death of Agrippa I. '''Later Epiphanes was betrothed to Drusilla’s sister Mariamne. In 49/50, the brother of Mariamne and Drusilla, King Agrippa II had cancelled the wedding between Epiphanes and Mariamne, because again Epiphanes refused to adopt the customs and religion of the Jews.'''
http://en.wikipedia.org/wiki/Antiochus_IV_of_Commagene
*>“Mariamne (born 34) was a daughter of King Herod Agrippa I. She was betrothed by her father to Gaius Julius Archelaus Antiochus Epiphanes, first son of King Antiochus IV of Commagene, but this marriage had not yet been enacted upon her father's death. '''Her brother Agrippa II enacted the marriage once he had been made tetrarch in around 49/50. From which marriage was derived a daughter, whose name was Berenice.'''
http://en.wikipedia.org/wiki/Mariamne_(daughter_of_Herod_Agrippa_I) this article is unreferenced.
*>'''Berenice was the daughter of Mariamne, (daughter of Herod Agrippa I), and Julius Archealus.[1] She was born sometime after 50 AD. After her parents had divorced, she lived with her mother in Alexandria.[2]'''
Notes
>>1.Josephus, Jewish Antiquities, xix. 9. § 1.
>>2.Josephus, Jewish Antiquities, xx.7.1
*http://en.wikipedia.org/wiki/Berenice_(daughter_of_Mariamne)
*http://en.wikipedia.org/wiki/Gaius_Julius_Archelaus_Antiochus_Epiph...
It seems to me to be doubtful that a relationship with an Herodian Princess would have been allowed to have been consummated unless legal ties had already been put in place. (Unless this 'Mary' claims another virgin birth :-).
The title 'of Commagene' attributed to her daughter also seems to me to indicate legitimate acknowledgement by the father.
Without other evidence, I'm offering the provisional theory that the relationship was NOT considered a legal marriage only by the Jewish authorities - because of his refusal to be circumcised-; but that, Mariamne's brother, Agrippa II, decided that he wasn't having the same situation occur as had when his father, Agrippa I was alive, when the marriage with Drusilla had fallen through on this point - and so went ahead with a legal Roman ceremony as sufficient.
This implies that Mariamne & Drusilla's brother - Agrippa II - was less of a devout Jew than his father. (Might he have been Christian? I must still check. His relationship with Josephus is in the era of the development of 'Christianised' Jews.)
Alternatively, it might be possible that Mariamne took matters into her own hands. Less likely, in my opinion, given the status of women - but her grandmother, Berenike, (for whom Mariamne's daughter is named) appears to have openly conducted an extra marital affair with Titus, so perhaps this isn't out of the question either.
