In religious iconography or mythological art, three separate beings may represent either a triad who always appear as a group or a single deity known from literary sources as having three aspects. In the case of the Irish Brigid it can be ambiguous whether she is a single goddess or three sisters, all named Brigid. The Morrígan also appears sometimes as one being, and at other times as three sisters, as do the three Irish goddesses of sovereignty, Ériu, Fódla and Banba.
Ériu, daughter of Ernmas of the Tuatha Dé Danann, was the eponymous matron goddess of Ireland.
The English name for Ireland comes from the name Ériu and the Germanic (Old Norse or Old English) word land.
Since Ériu is represented as goddess of Ireland, she is often interpreted as a modern-day personification of Ireland, although since the name “Ériu” is the older Irish form of the word Ireland, her modern name is often modified to “Éire” or “Erin” to suit a modern form.
With her sisters, Banba and Fódla, she was part of an important triumvirate of goddesses. When the Milesians arrived from Galicia, each of the three sisters asked that her name be given to the country. This was granted to them, although Ériu (Éire) became the chief name in use. (Banda and Fódla are still sometimes used as poetic names for Ireland.
Ériu, Banba and Fódla are interpreted as goddesses of sovereignty.
According to the seventeenth-century Irish historian Geoffrey Keating (Seathrún Céitinn), the three sovereignty goddesses associated with Éire, Banbha and Fódla were Badb, Macha and The Morrígan.
Different texts have attributed different personal relationships to Ériu. Her husband has been named as Mac Gréine (‘Son of the Sun’). She has also been portrayed as the lover of Elatha, a prince of the Fomorians, with whom she had a son Bres, and as the mistress of the hero Lugh. Her foster-father in the Rennes Dindsenchas was Codal the Roundbreasted, whose feeding Ériu caused the land in Ireland to heave toward the sky.