Aos Sí

Aos sí (pronounced [iːsˠ ˈʃiː]; English approximation: /iːs ˈʃiː/ eess SHEE; older form: aes sídhe [eːsˠ ˈʃiːə]) is the Irish name for a supernatural race in Gaelic folklore, similar to elves.

[8] Writing in the 7th century, the Irish bishop Tírechán described the sídh folk as "earthly gods" (Latin: dei terreni).

The fairies could either be fallen angels or the descendants of the Tuatha Dé Danann; in the latter case, this is equivalent with aos sí.

[1] 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 survivors of the Tuatha Dé Danann who retreated into the Otherworld when fleeing the mortal Sons of Míl Espáine who, like many other early invaders of Ireland, came from Iberia.

It is believed that infringing on these spaces will cause the aos sí to retaliate in an effort to remove the people or objects that invaded their homes.

[10] However, sidh in older texts refers specifically to "the palaces, courts, halls or residences" of the otherworldly beings that supposedly inhabit them.

The sluagh sídhe—"the fairy host"—is sometimes depicted in Irish and Scottish lore as a crowd of airborne spirits, perhaps the cursed, evil or restless dead.

The custom of offering milk and traditional foods—such as baked goods, apples or berries—to the aos sí has survived through the Christian era into the present day in parts of Ireland, Scotland and the diaspora.

[2] Those who maintain some degree of belief in the aos sí also are careful to leave their sacred places alone and protect them from damage through road or housing construction.