In Irish mythology, the aos sí (Irish pronunciation: [iːs ˈʃiː], older form aes sídhe [eːs ˈʃiːə]) are a powerful, supernatural race comparable to the fairies or elves. They are variously believed to live underground in the fairy mounds, across the western sea, or in an invisible world that coexists with the world of humans. This world is described in the Book of Invasions (Book of Leinster) as a parallel universe in which the aos sí walk amongst the living.
In the Irish language, aos sí means "people of the mounds" (the mounds are known in Irish as "the sídhe"). In Irish literature the people of the mounds are also referred to as the daoine sídhe ("deena shee"), and in Scottish Gaelic literature as the daoine sìth or daoine sìdh. They are variously believed to be the ancestors, the spirits of nature, or the goddesses and gods themselves.
In some later, English texts, writers have inaccurately referred to the aos sí as "the sídhe". While this is incorrect, it has become a widespread usage in English.
In Gaelic mythology
In many Gaelic tales, the aos sí are later, literary versions of the Tuatha Dé Danann ("people of the Goddess Danu" – the deities and deified ancestors of Irish mythology). Some sources describe them as the remaining survivors of the Tuatha Dé Danann who retreated into the Otherworld after they were defeated by the Milesians. According to the Lebor Gabála Érenn (The Book of Invasions) the Tuatha Dé Danann were defeated in battle by the Milesians – the mortal Sons of Míl Espáine who, like many other early invaders of Ireland, came from Spain. Geoffrey Keating, an Irish historian from the late 17th century, equates Spain with the Land of the Dead. Many scholars[who?] alive today agree with Keating’s opinion.
In Gaelic folklore
In folk belief and practice, the aos sí are often propitiated with offerings, and care is taken to avoid angering or insulting them. Often they are not named directly, but rather spoken of with euphemisms such as "The Good Neighbors," "The Fair Folk," or simply "The Folk", in the hope that if humans describe them as kind, they are more likely to be so. In this vein, the most common names for them, aos sí, aes sídhe, daoine sídhe (singular duine sídhe) and daoine sìth mean, literally, "people of peace".
Aos sí are sometimes seen as fierce guardians of their abodes – whether that be a fairy hill, a fairy ring, a special tree (often a hawthorn), or perhaps a particular loch or wood. The Gaelic Otherworld is seen as being closer at the times of dusk and dawn, therefore this is seen as a time special to the aos sí, as are some of the festivals such as Samhain, Beltane and Midsummer. The aos sí are generally described as stunningly beautiful, though they can also be terrible and hideous.
The sídhe: abodes of the aes sídhe
As part of the surrender terms in their loss against the Milesians, the Tuatha Dé Danann agreed to retreat and dwell underground in the sídhe (modern Irish: sí; Scottish Gaelic: sìth; Old Irish síde, singular síd), the hills or earthen mounds that dot the Irish landscape. In some of the later poetry, we find that each leader of one of the tribes of the Tuatha Dé Danann was given one mound.
In a number of later English language texts, the word sídhe was used for both the mounds and the people of the mounds. However, this is a modern phenomenon, and sidh in older texts refers specifically to "the palaces, courts, halls or residences" of "the ghostly beings which according to Gaedhelic mythology inhabited them" (O'Curry, E., Lectures on Manuscript Materials, Dublin 1861, p504, quoted by Evans-Wentz 1966, p291).
The fact that many of these sídhe have been found to be ancient burial mounds has contributed to the theory that the aos sí were the pre-Celtic occupants of Ireland. The Book of Invasions, the Annals of the Four Masters, and the oral history, all point in this direction.
Other views allow for these stories to be presented as a case of pure mythology, deriving from Greek cultural influence. The key arguments derive from a main source, Hesiod’s Works and Days. In Works and Days, Hesiod portrays the basic moral foundation and plantation techniques for citizens of Greece. He also paints a picture of the races of men, created by the Greek deities.
The story of the Aes Sídhe has been spread consistently over Scotland and Ireland, with many tales referring to how the Norse invaders drove Scottish inhabitants underground to live in the hills. This is just one part of the legend, and contributes specifically to the Changeling myth in Western-European folklore.
Types of aos sí
The Banshee or bean sídhe, which simply means "woman of the sídhe", has come to specifically indicate the supernatural women of Ireland who announce an oncoming death by their wailing and keening. Her counterpart in Scottish mythology is the bean shìth (sometimes spelled bean-shìdh). Other varieties of aos sí and daoine sìth include the Scottish bean nighe – the washerwoman who is seen washing the bloody clothing or armour of the person who is doomed to die; the leanan sídhe – the "fairy lover"; the Cat Sìth – a fairy cat; and the Cu Sìth – fairy dog.
The sluagh sídhe – "the fairy host" are sometimes depicted in Irish and Scottish lore as airborne spirits of an unpleasant nature, and perhaps the cursed, evil or restless dead. The siabhra (anglicized as "sheevra"), may be a type of these lesser spirits, prone to evil and mischief. However an Ulster folk song also uses "sheevra" simply to mean "spirit" or "fairy".