Alright, Emperor Caracalla, way back in 216, sent a request to the Parthian King Artabanus to marry his daughter (potentially creating a heir to both kingdoms). In all actuality, Caracalla massacred the diplomatic team sent to arrange the marriage and launched an invasion of Parthia. But, what if Caracalla actually successfully married Artabanus's daughter? Would a child of this union actually be recognized as a the Emperor of Rome and King of Parthia? Could the two nations actually ever function together as a union?