The name Herodion is confusing. The fortress called "The Herodion" was built by Herod the Great and evidently named out of love for himself.
Prince Herodion of later times was the firstborn son of Salome/Mary Magdalene, and was fathered either by Philip II/John the Baptist shortly before his death or FOR him shortly after his death by Aristobulus III/Jesus. In any event, Herodion would have been considered the legal heir of Philip II and represented the continuation of his line.
Herodion is mentioned in Romans 16:11, which reads: "Salute Herodion my kinsman." Herodion has been defined as "The Littlest Herod", but perhaps the name might better be understood as "The Fortress". If the statues of his descendants Trajan and Hadrian are any indication, he was solidly built. Herodion would have been the nephew of Paul. Both Philip II and Aristobulus III were the brothers of Phasaelus/Paul/Saulus. The three brothers were the sons of Antipater son of Herod the Great and Doris (Livia Drusilla). Considering the importance of Livia Drusilla, it should be of no surprise that her grandsons became so prominent.
© Charles N. Pope, US Library of Congress. All rights reserved.