Soon after the departure of the legions, 43 B. C., the young king Ptolemy died suddenly. Cleopatra was accused of having him poisoned. This crime, which is far from being authenticated, is by no means improbable. It may be that when Cleopatra by the departure of the Roman soldiers found herself without any reliable troops, she dreaded either a conspiracy in the palace or an insurrection which would drive her from the throne to place on it her brother. Six years previously the same circumstance had resulted to the advantage of her other brother, and Cleopatra had nearly fallen a victim. Immediately on the death of Ptolemy XIII., the queen took as the sharer of the throne her young son Ptolemy-Cæsarion, then four years of age.
Stationed at Cyprus was an Egytian fleet. Cassius sent orders direct to the navarch Sarapion, who commanded it, to unite with the republican fleet, and the latter obeyed without even referring to his sovereign. Not satisfied with the four legions and the squadron which he had already received from Cleopatra, much against her will, indeed, Cassius again sent her word to furnish him new supplies of troops, ships, provisions, and money. The queen, who feared an invasion, which she was without forces to repel, sought to temporize. She expressed her regrets to Cassius that she could not at once send him aid, Egypt being ruined by famine and pestilence. Famine indeed reigned there by reason of an insufficient inundation of the Nile, but Egypt was not ruined for all that, and whilst Cleopatra was evading the demands of Cassius she was preparing a new fleet to assist the Triumvirs. Cassius was not deceived by the diplomacy of Cleopatra’s envoy. He determined to invade Egypt. He had already set out on his march when Brutus, on the approach of the army of Antony, summoned him into Macedonia. Then Cleopatra sent her fleet to join the party of the Cæsarians, but on the way this fleet was dispersed and almost utterly destroyed by a tempest. Throughout this war ill-fortune seemed to pursue Cleopatra—with the best will to second the Triumvirs she had been able to give them almost no assistance; on the contrary, she had furnished reënforcements to the republicans, who, well knowing that these reënforcements had been most unwillingly supplied, desired to take vengeance for her reluctance.