Aos Sí
Supernatural race in Gaelic folklore, dwellers of fairy mounds.
The *aos sí* (pronounced ees SHEE) are a supernatural race from Gaelic folklore, often compared to elves. They are believed to descend from the Tuatha Dé Danann, the gods of Irish mythology. The name itself translates to "people of the mounds" or "folk of the síde," referring to the mounds where they live. These mounds are considered gateways to an Otherworld and are called "fairy mounds," "elf mounds," or "hollow hills" in English. The *aos sí* are known to interact with humans, and they are described variously as ancestors, nature spirits, or gods and goddesses. The word *aos sí* comes from *aos* ("people") and *sí* or *sídh*, the genitive form of *sí* or *sídh* ("fairy mound"), which traces back to the Proto-Celtic *sīdos* ("abode") and is related to "seat" and "settle." Another term, *daoine sí*, also means "people of the fairy mound." These names appear in Scottish Gaelic as *aos-sìthe* and *daoine-sìthe*. An individual member of the *aos sí* may be called a *síog*, anglicised as "sheogue". In English, they are often simply called "the Sidhe," though this usage is borrowed from the Irish genitive form *sídhe* (or *síde*), which does occur in Irish. In medieval Irish literature, *aes síde* and *fír síde* are used interchangeably with *Tuath Dé* and *Tuatha Dé Danann*, though *Tuath Dé* appears more in legendary history and mythology. The 7th-century bishop Tírechán called the *sídh* folk "earthly gods" (*dei terreni*). The 8th-century Fiacc's Hymn has been interpreted as suggesting that the Irish worshipped the *sídh* folk before Saint Patrick, but its phrasing is ambiguous and not a direct quote. Irish folklore offers two possible origins for fairies, due to its oral nature. They may be fallen angels whose sins were not severe enough for hell, or they are the descendants of the Tuatha Dé Danann—equivalent to the *aos sí*. In many tales, the *aos sí* are later versions of the Tuatha Dé Danann, deities and deified ancestors who retreated into the Otherworld after surrendering to the Milesians from Iberia. As part of their surrender, they agreed to live underground. In folk practice, the *aos sí* are often appeased with offerings to avoid angering them.
- Also known as
- Daoine sí, Sidhe, Fair Folk, Good Neighbours
- Origin
- Gaelic folklore; said to descend from the Tuatha Dé Danann
- Domain
- Supernatural race; dwell in fairy mounds (síde/sídhe)
- Associated festivals
- Samhain, Bealtaine, Midsummer
- Notable types
- Banshee (bean sídhe), leanan sídhe, cat-sìth, cù-sìth
Lore & Background
In medieval Irish literature, the names *aes síde* and *fír síde* refer to the fairy folk or people of the mounds, while *Tuath Dé* and *Tuatha Dé Danann* specifically denote the mythological race of gods. Though related, they are not synonymous; *Tuath Dé* tends to be used in contexts of legendary history and mythology. Writing in the 7th century, the Irish bishop Tírechán described the *sídh* folk as 'earthly gods' (Latin: *dei terreni*). The 6th or 7th century Fiacc's Hymn has been interpreted as suggesting that the Irish adored the *sídh* folk before the coming of Saint Patrick, but its phrasing is ambiguous and not a direct quote. Due to the oral nature of Irish folklore, the exact origins of the fairies are not well defined.
Reader's Guide
The aos sí represent a central element of Gaelic folklore and popular religion, bridging pre-Christian mythology and later folk Christianity. Their significance lies in their dual nature as both divine beings (descendants of the Tuatha Dé Danann) and as spirits of nature or ancestors, reflecting a worldview where the Otherworld is closely interwoven with the mortal realm. The term 'Creideamh Sí' (Fairy Faith) describes the collection of beliefs and practices observed by those who wish to keep good relationships with the aos sí and avoid angering them. This includes offering food and drink, and protecting their sacred places from damage. The aos sí have left a lasting legacy in Irish and Scottish culture, with figures like the banshee (bean sídhe) becoming widely known. Their association with liminal times—dusk, dawn, and festivals such as Samhain and Bealtaine—underscores their role as intermediaries between worlds. The term 'sídhe' itself, originally referring to the mounds, has in later English-language texts been incorrectly used for both the mounds and the people, a usage popularized by writers such as W. B. Yeats.
Did You Know?
- The term aos sí derives from aos, meaning 'people', and sídhe, the genitive form of síodh, meaning 'fairy mound'.
- The aos sí are often not named directly but referred to as 'The Good Neighbours', 'The Fair Folk', or simply 'The Folk'.
- The custom of offering milk and traditional foods to the aos sí has survived into the present day in parts of Ireland, Scotland and the diaspora.
Frequently Asked Questions
What are the Aos Sí?
The Aos Sí are a supernatural race in Gaelic folklore, often likened to elves or fairies in English-speaking traditions. They are also called the Sidhe, the Fair Folk, or the Good Neighbours, and are described variously as ancestral spirits, nature beings, or deities.
Where do the Aos Sí dwell?
They live in underground mounds known as sídhe (pronounced 'shees'), which are also called fairy mounds, elf mounds, or hollow hills. These mounds are regarded as portals into an Otherworld rather than mere burial sites.
What is the origin of the Aos Sí?
In Gaelic tradition, the Aos Sí are said to be the descendants of the Tuatha Dé Danann, the pantheon of gods from earlier Irish mythology. The name itself simply means 'people of the sí,' tying them directly to their mound-dwelling.
What kinds of beings belong to the Aos Sí?
Notable members include the bean sídhe (banshee), the leanan sídhe (a fairy lover), the cat-sìth (a fairy cat), and the cù-sìth (a fairy hound). Each serves a distinct role in the wider web of Gaelic supernatural lore.
When are the Aos Sí most closely associated with human activity?
Their presence is strongest around the seasonal festivals of Samhain, Bealtaine, and Midsummer, when the boundary between the human world and the Otherworld is thought to thin. This is when they are most likely to interact with or be seen by humans.
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