Mariamne was everything Herod wanted and everything he feared. A Hasmonean princess of extraordinary beauty, she gave him legitimate connection to the dynasty he had overthrown. Josephus writes in his <i>Antiquities</i> that Herod's love for her was obsessive, almost pathological. He could not stand to be apart from her, but he could not stop suspecting her either.
The crisis began when Herod left to meet Mark Antony, uncertain whether he would return alive. He placed Mariamne under the guard of a man named Sohemus with secret instructions: if Herod died, Sohemus was to kill her. Herod could not tolerate the idea of Mariamne living after him, possibly marrying someone else.
Sohemus, however, was gradually won over by Mariamne and her mother Alexandra. He revealed the king's secret order. When Herod returned triumphant from his meeting with Antony, Mariamne confronted him. She threw the death order in his face. Herod was stunned. The only way she could have learned the secret was from Sohemus, and the only reason Sohemus would have told her, Herod concluded, was if they were having an affair.
The accusation was almost certainly false. But Herod's sister Salome, who had long despised Mariamne, fanned the flames. She produced a servant who claimed Mariamne had tried to poison the king. A trial was held. Herod condemned his wife to death.
Josephus describes Mariamne's final moments with devastating clarity. She walked to her execution without a word of fear. She did not beg. She did not weep. Her composure was absolute. Alexandra, her own mother, publicly denounced her at the end, calling her ungrateful and deserving of death, in a transparent attempt to save herself from Herod's wrath.
The moment Mariamne was dead, Herod's grief consumed him. He wandered his palace calling her name. He ordered his servants to summon her as if she were still alive. He fell into a violent illness that his doctors feared would kill him. Josephus records that he withdrew to the desert near Samaria, hunting obsessively, trying to outrun a despair that never lifted.
Alexandra saw her chance and tried to seize the fortresses in Jerusalem. Herod, roused from his grief by the threat, had her executed too. Then he hunted down every remaining connection to the Hasmonean bloodline. Costobarus, Salome's ex-husband, had been secretly sheltering the sons of a Hasmonean loyalist named Babbas for twelve years. When Salome revealed this during their divorce, Herod had Costobarus and the sons of Babbas killed. The Hasmonean line was being systematically erased.