Arsinoe IV (c. 68/ 67 - 41 BC), was the fourth daughter of Ptolemy XII Auletes, sister of Ptolemy XIII and Cleopatra VII, and one of the last rulers of the Ptolemaic dynasty of ancient Egypt. When their father died, he left Ptolemy and Cleopatra as joint rulers of Egypt, but Ptolemy soon dethroned Cleopatra and forced her to flee Alexandria.

When Julius Caesar arrived in Alexandria in 48 BC and sided with Cleopatra's faction, Arsinoe escaped from the capital with her mentor Ganymedes and joined the Egyptian army under Achillas , assuming the title of pharaoh. When Achillas and Ganymedes clashed, Arsinoe had Achillas executed and placed Ganymedes in command of the army. Ganymedes initially enjoyed some success against the Romans, negotiating an exchange of Arsinoe for Ptolemy, but the Romans soon received reinforcements and inflicted a decisive defeat on the Egyptians.

Arsinoe was transported to Rome, where she was forced to appear in Caesar's triumph. She subsequently took sanctuary in the Temple of Artemis at Ephesus, attempting to find refuge from the ambitions of her old sister, Cleopatra. Her fears proved well-founded, for in 41 BC Mark Antony had Arsinoe executed at Cleopatra's instigation.

Reference

Encyclopædia Britannica, 2003 edition