Hastings' Dictionary of the Bible (1898)
HERO'DIANS, a Jewish political party, originating probably in devotion toward the Roman emperor and Herod, his deputy. Matt 22:16. They were the court-party and submitted willingly to the government of Rome, and were thus at the opposite pole from the Pharisees. It may be that some of them were among those who regarded Herod as the Messiah. They coalesced with the Pharisees in the attempt to destroy Christ, Mark 3:6; Matt 22:16, and are probably referred to in the expression "leaven of Herod," Mark 8:15.