>>6482873According to tradition, incestuous marriages between the pharaohs and their sisters were common. It could have been done to emulate the god Osiris and his sister/wife the goddess Isis and/or to keep the sacred bloodline pure.
In the 4th dynasty (2600-2450 BC), Khufu, the pharaoh who most scholars believe built the Great Pyramid of Giza, had a wife named Meritites who was maybe his sister or half-sister. Khufu's father Sneferu and his mother Hetepheres are also believed to have both been children of the pharaoh Huni. Khufu's son and successor Djedefre married his half sister Hetepheres who had previously been married to another brother or half-brother named Kawab with whom she produced a daughter, the future queen Meresankh.
Looking ahead to the 18th dynasty (1550-1300 BC), Thutmosis II was married to his sister Hatshetsup with whom he had a daughter. Thutmosis IV's second queen, Iaret, was probably his sister although again she was not the mother of his son and successor Amenhotep III. Finally, the famous King Tutankhamun's wife Ankhesenamen was probably either his half-sister or his niece.
When Alexander the Great's general Ptolemy seized control of Egypt around 323 BC, his descendants would continue the local custom of pharaonic brother-sister marriages. This practice was unknown among Greeks and Macedonians, and it earned Ptolemy II Philadelphos and his sister/wife Arsinoe the nickname "philadelphoi" meaning "brother loving."
Here the record is much clearer, with Greek and Egyptian historians giving us accounts of marriages between brother and sister and between uncle and niece ("double niece", meaning the daughter of his brother AND his sister) which produced offspring. Look at the attempted reconstruction of the Ptolemy family tree in the pic. It's open to some debate, but it gives you some idea of how inbred they became.
>TL:DR Cleo is most likely going to have to marry & eventually bang one of her little brothers because Egyptian tradition. 