Greek

In Greek mythology, Gaia (earth) had 12 children with her own son Uranus (sky).^[6][7] She bore six male and six female Titans to her son, Uranus (sky). The male Titans were Oceanus, Coeus, Crius, Hyperion, Iapetus, and Cronus. The female Titans were Theia, Rhea, Themis, Mnemosyne, Phoebe, and Tethys. Oceanus, Coeus, Hyperion and Cronus each consorted with one of their sisters and mated with them, producing offspring of their own,^[6] while Themis and Mnemosyne became wives of their nephew Zeus,^[8] Iapetus married his niece Clymene,^[9] and Crius married his half-sister Eurybia.^[10]

Zeus also fathered a daughter, Persephone, with his other older sister, Demeter.^[11] However, the orphic sources claim that Persephone was instead the daughter of Zeus and his mother Rhea.^[12]

Nyx and Erebus were also married siblings. The sea god Phorcys fathered many offspring by his sister Ceto.

Among the many lovers of Zeus, some were his daughters. Persephone is the daughter of Demeter and her brother Zeus, and becomes the consort of her uncle Hades. Some legends indicate that her father impregnated her and begat Dionysus Zagreus. Other examples include Zeus's relations with the Muse Calliope, Aphrodite (his daughter in some versions) and Nemesis (his daughter in one tradition).

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Egyptian

Horus, the grandson of Geb, had his own mother, Isis, become his imperial consort.^[14]

The goddess Hathor was simultaneously considered to be the mother, wife, and daughter of the sun god Ra.^[15] Hathor was also occasionally seen as the mother and wife of Horus.^{[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]: 107–115, 122–123, 145–146, 153–156, 187–188, 202–203 [31][32][33][34]}

In Egyptian mythology, there are frequent sibling marriages. For example, Shu and Tefnut are brother and sister and they produce offspring, Geb and Nut.^[7][35]

Inca

The patron god on the Incas, Inti, is married to his elder sister Mama Quilla.

Inuit

African

Chinese

In another myth, which went among the Miao people in the Yunnan Province, a great flood leaves only a mother and her young son alive. The mother accidentally eats a nut that transforms her into a young woman.^[40]

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Japanese

Indian

Numerous variants of brother-sister unions following the flood are found from the Bhuiya, Maria, Bondo, Gabada, Kond, Saora and Kol among the tribal area of central India. A variant of mother-son union following the flood is reported from the Gabada of the same location too.^[43]

Siberia

In an Udege myth, a girl and her younger brother are the sole survivors of a great flood. They became the progenitors of the whole human race.^[44]

Taiwanese

From Taiwan alone come twenty-eight versions of a brother-sister pair living as husband and wife to become the progenitors of mankind after a great flood.^[45]

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Fillipino

The Mandaya of Mindanao have a myth of a big flood killing all except a pregnant lady. A son, named Uacatan (Watakan), is born to her. When the son grows up, he weds his mother, and from this union all humans arise.^[43][47][48]

In the Philippines, brother-sister marriages following a flood are reported from the Ifugao, Isneg, and Igorot.^[43]

Korean

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Thai

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Greek

Norse

Njörðr is sometimes said to be married to Skaði, while other times he's said to be married to his unnamed sister. Ynglinga saga chapter 4, provides an example of the latter, characterizing their union as a Vanir custom:

Old Norse Þá er Njǫrðr var með Vǫnum, þá hafði hann átta systur sína, því at þat váru þar lǫg; váru þeira bǫrn Freyr ok Freyja.[52]

Lee M. Hollander translation (1992) While Njorth lived with the Vanir he had his sister as wife, because that was the custom among them. Their children were Frey and Freya.[53]

In Norse legends, the hero Sigmund and his sister Signy murdered her children and begot a son, Sinfjötli. When Sinfjötli had grown up, he and Sigmund murdered Signy's husband Siggeir. The element of incest also appears in the version of the story used in Wagner's opera-cycle Der Ring des Nibelungen, in which Siegfried is the offspring of Siegmund and his sister Sieglinde.

The legendary Danish king Hrólfr kraki was born from an incestuous union of Halgi and Yrsa.^[54]

Chinese

In Chinese mythology, Fu Xi is a king and creator god who takes his sister, the goddess Nüwa, as his bride.^[55][56][57]

Icelandic

In Icelandic folklore a common plot involves a brother and sister (illegally) conceiving a child. They subsequently escape justice by moving to a remote valley. There they proceed to have several more children. The man has some magical abilities which he uses to direct travelers to or away from the valley as he chooses. The siblings always have exactly one daughter but any number of sons. Eventually the magician allows a young man (usually searching for sheep) into the valley and asks him to marry the daughter and give himself and his sister a civilized burial upon their deaths. This is subsequently done.

British/Irish

In the Old Irish saga Tochmarc Étaíne ("The Wooing of Étaín"), Eochaid Airem, the high king of Ireland is tricked into sleeping with his daughter, whom he mistakes for her mother Étaín. The child of their union becomes the mother of the legendary king Conaire Mor.

In some versions of the medieval British legend of King Arthur, Arthur accidentally begets a son by his half sister Morgause in a night of blind lust, then seeks to have the child killed when he hears of a prophecy that it will bring about the undoing of the Round Table. The child survives and later becomes Mordred, his ultimate nemesis.^[58]

Danand, a minor character in Irish mythology, is said to have conceived three sons with her own father.^[59][60]

Vietnamese

In an ancient Vietnamese folklore, there is a tale of a brother and a sister. As children, the brother and sister fought over a toy. The brother smashes a stone over his sister's head, and the girl falls down unconscious. The boy thinks he has killed his sister, and afraid of punishment, he flees. Years later, by coincidence, they meet again, fall in love, and marry without knowing they are siblings. They build a house along a seashore, and the brother becomes a fisherman while his sister tends to the house. Together they have a son. One day, the brother discovers a scar on his wife's head. She tells him about the childhood fight with her brother, and the brother realizes that he has married his own sister. Overwhelmed with guilt over his incest, the brother goes out on the sea. Every day, the sister climbs to the top of the hill to look for her brother, but he never comes back. She died in waiting and became "Hon Vong Phu" ("the stone waiting for her husband").^{[61][62][63][64][65][66][67][68][69][70]}

Ugandan

In a tale from Uganda, a youth called Uken was having a playful argument with his mother. "Now you are old, mother," said he. "But was I not a girl once too?" countered his mother, "surely if I dressed up the men young as you would look at me still! "Really, mother," answered Uken, "you who are all old now, who do you think would look at you?" Now when his mother heard what he said, his words sank deep in her heart. The next morning Uken was exchanging promises with a girl friend, and the girl promised that she would come to him that night. Meanwhile, Uken's mother wanted to disprove her son's earlier opinion of her. She stripped off all her old skin and there she was with complexion as clear as long ago when she had been a girl. Then she went to her son's sleeping place, and waited for him, wanting to see his reaction. She waited and waited but sleep began to overwhelm her and overwhelmed her it did. By the time the youth came back from his walk it was night. He found his mother asleep on his sleeping place. She looked so young and beautiful from head to foot, glistening with the oil she had used to anoint her body, and wearing beads of many kinds.' There she was lying on his sleeping place. So when her son came and entered the hut his eye lit up at the thought that perhaps the girl who had made him promises had really come. And so he lay with his mother that night. At first light his mother went out and left him on the bed. She had never intended for this to happen nor did she think her son knew he had spent the night sleeping with his mother as if he was her husband so she decided she would take this secret to her grave. She returned to her hut and put on her old skin. Then when morning came Uken got up and went to his mother's hut to ask her for food, and once again made some comment about her old age. Hearing that, she could not help herself and said "Your mother, your mother, did you know that just a few hours ago you were enjoying the night with this old lady?" Uken was shocked, and knew it to be true as he realized the moans and sighs of his woman last night matched the voice of his mother. Mortified and embarrassed, never again did he disrespect his mother's appearance.^[71]

Other

In fairy tales of Aarne-Thompson folktale type 510B, the persecuted heroine, the heroine is persecuted by her father, and most usually, the persecution is an attempt to marry her, as in Allerleirauh or Donkeyskin. This was taken up into the legend of Saint Dymphna. In addition, stories of tale type ATU 706, "The Maiden Without Hands", also show the motif of attempted fatherly incest connected with the mutilation of the heroine.^[72]

Several child ballads have the motif of incest between brothers and sisters who are raised apart. This is usually unwitting (as in The Bonny Hind and Sheath and Knife, for example), but always brings about a tragic end.