The Morrígan is primarily associated with fate, especially with foretelling doom and death in battle. In this role she appears as a crow, flying above the battlefield. The Morrígan has thus been likened to the Valkyries and Norns of Germanic mythology. She is also associated with sovereignty, and her connection with cows may also suggest an association with wealth and the land.
The Morrígan is often described as a trio of individuals, all sisters, called 'the three Morrígna'. Although membership of the triad varies, the most common combination in modern sources is Badb, Macha and Nemain. However the primary sources indicate a more likely triad of Badb, Macha and Anand; Anand is also given as another name for the Morrígan. Other accounts name Fea and others.
There is some disagreement over the meaning of the Morrígan's name. Mor may derive from an Indo-European root connoting terror or monstrousness, cognate with the Old English maere (which survives in the modern English word "nightmare") and the Scandinavian mara and the Old Russian "mara" ("nightmare"); while rígan translates as 'queen'. This can be reconstructed in Proto-Celtic as *Moro-rīganī-s. Accordingly, Morrígan is often translated as "Phantom Queen". This is the derivation generally favoured in current scholarship.
In the Middle Irish period the name is often spelled Mórrígan with a lengthening diacritic over the 'o', seemingly intended to mean "Great Queen" (Old Irish mór, 'great'; this would derive from a hypothetical Proto-Celtic *Māra Rīganī-s). Whitley Stokes believed this latter spelling was due to a false etymology popular at the time. There have also been attempts by modern writers to link the Morrígan with the Welsh literary figure Morgan le Fay from Arthurian romance, in whose name 'mor' may derive from a Welsh word for 'sea', but the names are derived from different cultures and branches of the Celtic linguistic tree.
Glosses and glossaries
The earliest sources for the Morrígan are glosses in Latin manuscripts, and glossaries (collections of glosses). In a 9th-century manuscript containing the Latin Vulgate translation of the Book of Isaiah, the word Lamia is used to translate the Hebrew Lilith. A gloss explains this as "a monster in female form, that is, a morrígan". Cormac's Glossary (also 9th century), and a gloss in the later manuscript H.3.18, both explain the plural word gudemain ("spectres") with the plural form morrígna. The 8th century O'Mulconry's Glossary says that Macha is one of the three morrígna.
The Morrígan's earliest narrative appearances, in which she is depicted as an individual, are in stories of the Ulster Cycle, where she has an ambiguous relationship with the hero Cú Chulainn. In Táin Bó Regamna (The Cattle Raid of Regamain), Cúchulainn encounters the Morrígan, but does not recognise her, as she drives a heifer from his territory. In response to this perceived challenge, and his ignorance of her role as a sovereignty figure, he insults her. But before he can attack her she becomes a black bird on a nearby branch. Cúchulainn now knows who she is, and tells her that had he known before, they would not have parted in enmity. She notes that whatever he had done would have brought him ill luck. To his response that she cannot harm him, she delivers a series of warnings, foretelling a coming battle in which he will be killed. She tells him, "it is at the guarding of thy death that I am; and I shall be."
In the Táin Bó Cuailnge queen Medb of Connacht launches an invasion of Ulster to steal the bull Donn Cuailnge; the Morrígan, like Alecto of the Greek Furies, appears to the bull in the form of a crow and warns him to flee. Cúchulainn defends Ulster by fighting a series of single combats at fords against Medb's champions. In between combats the Morrígan appears to him as a young woman and offers him her love, and her aid in the battle, but he rejects her offer. In response she intervenes in his next combat, first in the form of an eel who trips him, then as a wolf who stampedes cattle across the ford, and finally as a white, red-eared heifer leading the stampede, just as she had warned in their previous encounter. However Cúchulainn wounds her in each form and defeats his opponent despite her interference. Later she appears to him as an old woman bearing the same three wounds that her animal forms sustained, milking a cow. She gives Cúchulainn three drinks of milk. He blesses her with each drink, and her wounds are healed. He regrets blessing her for the three drinks of milk which is apparent in the exchange between the Morrígan and Cúchulainn, "She gave him milk from the third teat, and her leg was healed. 'You told me once,' she said,'that you would never heal me.' 'Had I known it was you,' said Cúchulainn, 'I never would have.'" As the armies gather for the final battle, she prophesies the bloodshed to come.
In one version of Cúchulainn's death-tale, as Cúchulainn rides to meet his enemies, he encounters the Morrígan as a hag washing his bloody armour in a ford, an omen of his death. Later in the story, mortally wounded, Cúchulainn ties himself to a standing stone with his own entrails so he can die upright, and it is only when a crow lands on his shoulder that his enemies believe he is dead.
The Morrígan also appears in texts of the Mythological Cycle. In the 12th century pseudohistorical compilation Lebor Gabála Érenn she is listed among the Tuatha Dé Danann as one of the daughters of Ernmas, granddaughter of Nuada.
The first three daughters of Ernmas are given as Ériu, Banba, and Fódla. Their names are synonyms for Ireland, and they were married to Mac Cuill, Mac Cécht, and Mac Gréine, the last three Tuatha Dé Danann kings of Ireland. Associated with the land and kingship, they probably represent a triple goddess of sovereignty. Next come Ernmas's other three daughters: Badb, Macha, and the Morrígan. A quatrain describes the three as wealthy, "springs of craftiness" and "sources of bitter fighting". The Morrígu's name is also said to be Anand, and she had three sons, Glon, Gaim, and Coscar. According to Geoffrey Keating's 17th century History of Ireland, Ériu, Banba, and Fódla worshipped Badb, Macha, and the Morrígan respectively.
The Morrígan also appears in Cath Maige Tuireadh (The Battle of Mag Tuired). On Samhain she keeps a tryst with the Dagda before the battle against the Fomorians. When he meets her she is washing herself, standing with one foot on either side of the river Unius. In some sources she is believed to have created the river. After they have sex, the Morrígan promises to summon the magicians of Ireland to cast spells on behalf of the Tuatha Dé, and to destroy Indech, the Fomorian king, taking from him "the blood of his heart and the kidneys of his valour". Later, we are told, she would bring two handfuls of his blood and deposit them in the same river (however, we are also told later in the text that Indech was killed by Ogma).
As battle is about to be joined, the Tuatha Dé leader, Lug, asks each what power they bring to the battle. The Morrígan's reply is difficult to interpret, but involves pursuing, destroying and subduing. When she comes to the battlefield she chants a poem, and immediately the battle breaks and the Fomorians are driven into the sea. After the battle she chants another poem celebrating the victory and prophesying the end of the world.
In another story she lures away the bull of a woman named Odras. Odras then follows the Morrígan to the Otherworld, via the cave of Cruachan. When Odras falls asleep, the Morrígan turns her into a pool of water.
Nature and functions
The Morrígan is often considered a triple goddess, but this triple nature is ambiguous and inconsistent. These triple appearances are partially due to the Celtic significance of threeness.  Sometimes she appears as one of three sisters, the daughters of Ernmas: Morrígan, Badb and Macha. Sometimes the trinity consists of Badb, Macha and Anand, collectively known as the Morrígna. Occasionally Nemain or Fea appear in the various combinations. However, the Morrígan can also appear alone, and her name is sometimes used interchangeably with Badb.
The Morrígan is usually interpreted as a "war goddess": W. M. Hennessy's "The Ancient Irish Goddess of War", written in 1870, was influential in establishing this interpretation. Her role often involves premonitions of a particular warrior's violent death, suggesting a link with the Banshee of later folklore. This connection is further noted by Patricia Lysaght: "In certain areas of Ireland this supernatural being is, in addition to the name banshee, also called the badhb". Her role was to not only be a symbol of imminent death, but to also influence the outcome of war. Most often she did this by appearing as a crow flying overhead and would either inspire fear or courage in the hearts of the warriors. In some cases, she is written to have appeared in visions to those who are destined to die in battle by washing their bloody armor. In this specific role, she is also given the role of foretelling imminent death with a particular emphasis on the individual. There are also a few rare accounts where she would join in the battle itself as a warrior and show her favouritism in a more direct manner.
It has also been suggested that she was closely tied to Irish männerbund groups (described as "bands of youthful warrior-hunters, living on the borders of civilized society and indulging in lawless activities for a time before inheriting property and taking their places as members of settled, landed communities") and that these groups may have been in some way dedicated to her. If true, her worship may have resembled that of Perchta groups in Germanic areas.
However, Máire Herbert has argued that "war per se is not a primary aspect of the role of the goddess", and that her association with cattle suggests her role was connected to the earth, fertility and sovereignty; she suggests that her association with war is a result of a confusion between her and the Badb, who she argues was originally a separate figure. She can be interpreted as providing political or military aid, or protection to the king—acting as a goddess of sovereignty, not necessarily a war goddess. There have been many cases where, after having been a cause of strife, the Morrigan has in turn become one of great help when a certain level of respect has been shown.
There is a burnt mound site in County Tipperary known as Fulacht na Mór Ríoghna ('cooking pit of the Mórrígan'). The fulachtaí sites are found in wild areas, and usually associated with outsiders such as the Fianna and the above-mentioned männerbund groups, as well as with the hunting of deer. The cooking connection also suggests to some a connection with the three mythical hags who cook the meal of dogflesh that brings the hero Cúchulainn to his doom. The Dá Chich na Morrigna ('two breasts of the Mórrígan'), a pair of hills in County Meath, suggest to some a role as a tutelary goddess, comparable to Anu, who has her own hills, Dá Chích Anann ('the breasts of Anu') in County Kerry. Other goddesses known to have similar hills are Áine and Grian of County Limerick who, in addition to a tutelary function, also have solar attributes.
There have been attempts by some modern authors of fiction to link the Arthurian character Morgan le Fay with the Morrígan. Morgan first appears in Geoffrey of Monmouth's Vita Merlini (The Life of Merlin) in the 12th century. In these Arthurian legends, such as Sir Gawaine and the Green Knight, Morgan is portrayed as an evil hag whose actions set into motion a bloody trail of events that lead the hero into numerous instances of danger. Morgan is also depicted as a seductress, much like the older legends of the goddess and has numerous sexual encounters with Merlin. The character is frequently depicted of wielding power over others to achieve her own purposes, allowing those actions to play out over time, to either the benefit or detriment of other characters. 
However, while the creators of the literary character of Morgan may have been somewhat inspired by the much older tales of the goddess, the relationship ends there. Scholars such as Rosalind Clark hold that the names are unrelated, the Welsh "Morgan" (Wales being the source of Arthurian legend) being derived from root words associated with the sea, while the Irish "Morrígan" has its roots either in a word for "terror" or a word for "greatness".
- Aldhouse-Green, Miranda (2015). The Celtic Myths: A Guide To The Ancient Gods And Legends. New York: Thames & Hudson. p. 125. ISBN 978-0-500-25209-3.
- Sjoestedt, Marie-Louise. Celtic Gods and Heroes. Dover Publications. pp. 31–32. ISBN 0-486-41441-8.
- O hOgain, Daithi (1991). Myth, Legend and Romance: An Encyclopedia of the Irish Folk Tradition. Oxford: Prentice Hall Press. pp. 307–309. ISBN 0-13-275959-4.
- Davidson, Hilda Ellis (1988). Myths and symbols in pagan Europe: early Scandinavian and Celtic religions. Syracuse: Syracuse University Press. p. 97. ISBN 0-8156-2441-7.
- MacKillop, James (1998). Dictionary of Celtic mythology. Oxford: Oxford University Press. pp. 335–336. ISBN 0-19-280120-1.
- Lebor Gabála Érenn §62, 64: "Badb and Macha and Anand... were the three daughters of Ernmas the she-farmer." "Badb and Morrigu, whose name was Anand."
- Dictionary of the Irish Language (DIL), Compact Edition, Royal Irish Academy, 1990, pp. 467–468
- DIL p. 507.
- Proto-Celtic – English wordlist; EtymologyOnline: "nightmare"
- Rosalind Clark (1990) The Great Queens: Irish Goddesses from the Morrígan to Cathleen Ní Houlihan (Irish Literary Studies, Book 34) ISBN 0-389-20928-7
- Alexander McBain, An Etymological Dictionary of the Gaelic Language, 1911: mór, ribhinn
- Stokes, Whitley (1891) Notes to "The Second Battle of Moytura" in Revue Celtique xii, p. 128.
- Isaiah 34:14 "And wild beasts shall meet with hyenas, the satyr shall cry to his fellow; yea, there shall the night hag alight, and find for herself a resting place." (Revised Standard Version, emphasis added)
- Angelique Gulermovich Epstein, War Goddess: The Morrígan and her Germano-Celtic Counterparts, electronic version, #148, (September 1998), pp. 45–51.
- DIL p. 372
- Táin Bó Regamna, Corpus of Electronic Texts Edition, p.33, Author: Unknown
- "The Cattle Raid of Regamna", translated by A. H. Leahy, from Heroic Romances of Ireland Vol II, 1906
- Cecile O'Rahilly (ed & trans), Táin Bó Cuailnge Recension 1, 1976, p. 152
- Cecile O'Rahilly (ed & trans), Táin Bó Cuailnge Recension 1, 1976, pp. 176–177, 180–182; Cecile O'Rahilly (ed & trans), Táin Bó Cualnge from the Book of Leinster, 1967, pp. 193–197
- Ciaran Carson, "The Táin: A New Translation of the Táin Bó Cúlailnge, 2007, pp. 96
- Cecile O'Rahilly (ed & trans), Táin Bó Cuailnge Recension 1, 1976, pp. 229–230
- "The Death of Cú Chulainn"
- Geoffrey Keating, The History of Ireland Book 2 Section 11
- 'The Second Battle of Moytura, translated by Whitley Stokes
- Cath Maige Tuired: The Second Battle of Mag Tuired, Text 166, Author: Unknown
- Elizabeth A. Gray (ed. & trans.), Cath Maige Tuired: The Second Battle of Mag Tuired, section 167, 1982
- "Odras", from The Metrical Dindshenchas Vol 4, translated by E. Gwynn
- Macalister, R.A.S. (trans.) (1941). Lebor Gabála Érenn: Book of the Taking of Ireland Part 1-5. Dublin: Irish Texts Society.
- W. M. Hennessy, "The Ancient Irish Goddess of War", Revue Celtique 1, 1870–72, pp. 32–37
- Patricia Lysaght, The Banshee: The Irish Death Messenger, 1986, ISBN 1-57098-138-8, p. 15
- Rolleston, T. W. (1911). Celtic Myths And Legends. New York: Barnes and Noble. ISBN 978-0-7607-8335-1.
- Arthur Cotterell, "The Encyclopedia of Mythology", 2010, pp. 102, pp. 152
- Angelique Gulermovich Epstein, "War Goddess: The Morrígan and her Germano-Celtic Counterparts", electronic version, #148 (September 1998)
- Maire West, "Aspects of díberg in the tale Togail Bruidne Da Derga", Zeitschrift für Celtische Philologie vol. 49–50, p. 950
- Carlo Ginzburg, Ecstasies: Deciphering the Witches' Sabbath, New York, Pantheon Books, 1991, ISBN 0-394-58163-6, pp. 6–7, 91, 101–2, 115 (note 47), 146 (note 62), 193, 182–204, 262, as well as numerous related references throughout Parts Two and Three
- Máire Herbert, "Transmutations of an Irish Goddess", in Miranda Green & Sandra Billington (ed.), The Concept of the Goddess, 1996
- Morgan le Fay in Sir Gawain and the Green Knight.
- Clark (1990) pp. 21–23, 208n.5
- Rosalind Clark, The Great Queens: Irish Goddesses from the Morrígan to Cathleen Ní Houlihan (Irish Literary Studies, Book 34)
- Barry Cunliffe, The Ancient Celts
- Miriam Robbins Dexter, Whence the Goddesses: A Source Book
- James MacKillop, Dictionary of Celtic Mythology
- Daithi O hOgain, Myth, Legend and Romance: An Encyclopedia of the Irish Folk Tradition Prentice Hall Press, (1991) : ISBN 0-13-275959-4
- Anne Ross, Pagan Celtic Britain: Studies in Iconography
- Anne Ross, "The Divine Hag of the Pagan Celts", in V. Newall (ed.), The Witch Figure.
- War Goddess: the Morrígan and her Germano-Celtic Counterparts thesis by Angelique Gulermovich Epstein (ZIP format)