The most famous of these relationships were in the Ptolemaic royal family; Cleopatra VII was married to two of her younger brothers, Ptolemy XIII and Ptolemy XIV, whilst her mother and father, Cleopatra V and Ptolemy XII, were also brother and sister. Arsinoe II and her younger brother Ptolemy II Philadelphus were the first in the family to participate in a full-sibling marriage, a departure from custom. A union between full siblings was counternormative in Greek and Macedonian tradition, and prohibited by the laws of at least some cities.
The most famous of these relationships were in the Ptolemaic royal family; Cleopatra VII was married to two of her younger brothers, Ptolemy XIII and Ptolemy XIV, whilst her mother and father, Cleopatra V and Ptolemy XII, were also brother and sister. Arsinoe II and her younger brother Ptolemy II Philadelphus were the first in the family to participate in a full-sibling marriage, a departure from custom. A union between full siblings was counternormative in Greek and Macedonian tradition, and prohibited by the laws of at least some cities.