You can only have one queen
Arsinoë glowered at the inscriptions on the wall; they glorified her ancestor, the first Ptolemy, but she found the mere thought of a Ptolemy infuriating. Not that men with other names didn’t present problems. Achillas or Ganymede. She would have to choose. Ganymede, the tutor she’d known for years, who had helped her escape, or Achillas, who she’d barely met, who had murdered Pompey and brought Caesar to Alexandria in fury, who also commanded the loyalty of the army? Of course, Achillas didn’t just want to be general; she pretended not to hear the whispers that he planned to make himself pharaoh by marrying the youngest royal sister.
At the thought of royal sisters Arsinoë got up and wandered restlessly about the room. Her older sister Cleopatra had made her choice, sharing Caesar’s bed so that she wouldn’t have to share her throne with their brother Ptolemy, the husband she didn’t want. And before that, while Arsinoë was still a child, their oldest sister had killed a husband that she didn’t want. And earlier still, her father’s first wife had seized his throne. Arsinoë smiled; Achillas should be careful, wanting to marry a queen of the line of Ptolemy. They were dangerous prizes, harder to keep than they were to win.
Ganymede couldn’t even try for the prize – he was a eunuch. Not that she wanted to marry him, but he was the only one she could trust. She wanted to keep him close, but he and Achillas hated each other. And the army followed Achillas. Arsinoë sat down and glared at the wall again. She couldn’t get rid of Achillas, but neither could he get rid of her. He couldn’t be king without a queen of the royal blood. She sat for some time, glaring at the wall while the lamp burned low. Her thoughts returned to her sister, who had moved so quickly to catch Caesar. Too quickly, maybe. Her hasty liaison with Caesar had ended with the two of them trapped in the city, while Arsinoë was free outside. Arsinoë would not make the same mistake with her general. She would keep him as general, and give him no cause to be jealous of Ganymede. But she would not be his queen.
She stood up and called the guard.
“Send for Achillas. We would speak with him.”
And so it was that great Caesar was slain in Alexandria, killed by a woman and for a woman, when the Egyptians under their queen Arsinoë stormed the palace. Cleopatra also died, but by her own hand. They say she took poison rather than be her sister’s prisoner. The young king Ptolemy was spared, as Queen Arsinoë had promised that she would marry him and together they would rule as king and queen of Egypt. The general Achillas was given great honour, and the queen herself presented him with a golden barge. But the general was not pleased that young Ptolemy sat beside Arsinoë; it was whispered that the general had thought to marry the queen himself. And when a few years later Ptolemy was found dead, all people believed that Achillas had ordered his death. Her youngest brother having died as well, the queen then sought a husband from among the Parthians. She contracted a marriage with Pacorus, who aspired to replace his father as lord of the Parthian empire. Together, Arsinoë and Pacorus raised an army and after many battles overthrew King Orodes. So it was that a princess of the line of Ptolemy Soter became queen of much of the empire which had once been Alexander’s.
So great was her empire, and so fearsome her armies, that even mighty Rome could do nothing against her. Octavian, who became Augustus, met her in battle more than once, but it was at the battle of Antioch, where both the Roman emperor and the Egyptian queen came with their armies, that the matter was settled. Queen Arsinoë won, and Augustus was forced to flee. Arsinoë could have seized even the city of Rome, but she had ever said that the Romans were upstarts, while she was of ancient royal lineage. She was content to be Queen of the East.
And there followed an age of peace under her reign. When she died, an old woman, she left her throne to her grandson, Ptolemy Ganymede.
Cassius Dio, Roman History
What really happened…
Arsinoë made the wrong call: she had Achillas executed and promoted Ganymede, alienating the army. In short order she was handed over to Caesar in exchange for her brother Ptolemy. Caesar took her back to Rome and displayed her in his triumph, although the would-be queen managed to score a small victory; the Roman public called for mercy, and so rather than being strangled, she was sent into exile in Ephesus, a religious sanctuary.
Time passed, Caesar was stabbed, Rome had a civil war, and about five years later Cleopatra got Mark Antony to arrange Arsinoë’s murder at Ephesus, a murder which flouted all the rules regarding sanctuary in the ancient world.