Oenghus is the son of the Dagda, ruler of an other-dimensional realm of beings known as the Tuatha de Danaan, a race of beings who were worshipped as gods by the Ancient Celts and Gaels of Western Europe, and Boann, the goddess of the Boyne River of County Meath in Eire (modern Ireland). Boann was the wife of the water-god, Nechtan, who settled Brugh na Boinne after the defeat of the Fomore, the eternal enemies of the Danaans. As Chieftain of the Tuatha de Danaan, the Dagda sent Nechtan on a day long errand, and in his absence, seduced Boann. Using his mystical powers, the Dagda extended the day to last nine months so that Boann conceived and gave birth to Oenghus in a single day. Oenghus was given to his brother, Mider, to be raised to adulthood, but when Oenghus became an adult, Nechtan gave Brugh na Boinne to Oenghus, possibly seeing him as his only worthy heir.
The Tuatha de Dannan were worshipped as gods throughout Ireland, Britain and Western Europe with the Dagda as King of Eire and Oenghus taking his throne in his absence. However, when the Dagda retired from Earthly rule, he split Eire up among four counties among his sons with Oenghus acquiring Leinster, Mider receiving Connacht, Oghma receiving Ulster and his brother Bodb Derg receiving Munster. Bodb as the eldest son also acquired the title as King of Eire at Meath, kept separate from the other four counties. During the Milesian invasion, the Danaans departed Earth for the realm of Otherworld connected to the Earth's dimension by way of countless sidhs or faerie mounds throughout Eire. Oenghus's sidh was located at Brugh na Boinne.
Oenghus took Derbrenn, the daughter of King Eochaidh Airem of Eire as his wife, but he eventually fell in love with Caer, the daughter of Ethal Anubal and grand-daughter of King Ailill and Medhbha of Connacht. Caer had appeared to him in a vision, and Oenghus turned to his older brother, Bodb, in order to identify and find the mystery woman in the vision. Using his spells, Bodb finally found Caer a year after the dream alongside the bank of a lake in Connacht with her numerous sisters. Oenghus approached Ethal Anubal for the right to court Caer. He learned that Caer was actually a mortal shapeshifter with her sisters, only able to live half a year on Earth in human form and the other half of the year as a swan.
The reason for this spell is unrevealed, but Oenghus learned from King Ailill that the best way to court Caer was to take her as a swan and convince her to remain human. Following his instructions, Oenghus confronted Caer on the Feast of Samhain and followed her into the sky as she turned to a swan, becoming a swan himself. Enchanting a mystical spell to her in song, he finally encouraged her to fly away with him to Brugh na Boinne to live as his wife. After he out-lived her, he took a third wife, Nuamaisi...READ MORE...
