Which woman was the sister of XXX?
Caesarion
Ptolemy XV Philopator Philometor Caesar (Greek: Πτολεμαῖος ΙΕʹ Φιλοπάτωρ Φιλομήτωρ Καῖσαρ, Ptolemaios IEʹ Philopatōr Philomētōr Kaisar; Latin: Ptolemaeus XV Philopator Philomētor Caesar; June 23, 47 BC -- August 23, 30 BC), better known by the nicknames Caesarion (/sᵻˈzæriən/; Greek: Καισαρίων, Kaisariōn, literally ``little Caesar''; Latin: Caesariō) and Ptolemy Caesar (/ˈtɒlᵻmi ˈsiːzər/; Greek: Πτολεμαῖος Καῖσαρ, Ptolemaios Kaisar; Latin: Ptolemaeus Caesar), was the last king of the Ptolemaic dynasty of Egypt, who reigned jointly with his mother Cleopatra VII of Egypt, from September 2, 44 BC. He held the position of sole ruler between the death of Cleopatra, on August 12, 30 BC, up to August 23, 30 BC, the time his death was ordered by Octavian, who would become the Roman emperor Augustus.