Herod sent his sons to Rome for an education. They came home polished, handsome, and walking straight into the deadliest family feud in Jewish royal history.
Alexander and Aristobulus, the sons of Herod's executed wife Mariamne, returned from Italy as young men the people adored. They had the look of royalty, the bearing of princes educated in the imperial capital, and one fatal flaw: they openly mourned their mother. That made them dangerous. Every time they grieved Mariamne's death, Salome, Herod's sister, heard a threat. She had helped engineer Mariamne's execution, and she assumed these boys would one day return the favor.
So Salome launched a campaign of whispers. She told Herod his sons were plotting revenge. She said they were telling the court their mother had been murdered. According to Josephus in Antiquities XVI, the young princes did themselves no favors. Their grief was public and bitter. They complained about wearing their dead mother's robes. They openly threatened that when they came to power, they would reduce their father's allies to common laborers.
Herod tried to manage the crisis. He brought in Archelaus, king of Cappadocia and father-in-law to Alexander, who managed a temporary reconciliation. But Salome and Pheroras, Herod's brother, kept stoking the fire. Pheroras told Alexander that Herod was making advances toward his wife Glaphyra, a lie designed to turn son against father permanently.
Eventually Herod hauled his sons before Augustus Caesar himself to adjudicate the dispute. Augustus brokered a fragile peace, declared that the sons should obey their father, and sent everyone home. Herod told the nation his sons would succeed him: Antipater first, then Alexander and Aristobulus. The crowd applauded. The plotters sharpened their knives. Nobody believed the peace would hold, and nobody was wrong.