 As the most powerful of Rome's eastern vassals, Egypt was indispensable in Rome's planned military invasion of the Parthian Empire.At Cleopatra's request, Antony ordered the execution of Arsinoe, who, though marched in Caesar's triumphal parade in 46 BC, had been granted sanctuary at the temple of Artemis in Ephesus.Antony and Cleopatra then spent the winter of 41 BC together in Alexandria.