 But, on the other hand, a certain degree of vanity and a spirit of vindictiveness, which marked him no less than his prepossessing qualities, rendered him extremely unpopular with the partisans of Herod, who had much to fear from a future King Alexander.Salome repeatedly warned Herod of danger threatening him from Alexander and his brother Aristobulus.The king felt that it was not impossible that his sons meditated revenge for Mariamne's execution; and on the other hand, the open antipathy expressed by them against their father combined to open the king's ear to the calumnies of Salome and her fellow-plotters.