Banshees are creatures from Irish mythology. It is said that when a citizen from an Irish village died, a woman, also referred to as "keeners", would sing a traditional lament or modern Irish caoineadh (pronounced kweenyah) at their funeral. However, they can only cry for five great Gaelic families: the O'Gradys, the O'Neills, the O'Briens, the O'Connors, and the Kavanaghs (this list has extended with intermarriages). Tales recount a fairy woman was associated with them and would make an appearance after a death in the family, making an appearance or sound to intimation of the death.
When these narratives were first translated into English, a distinction between the "banshee" and other fairy folk was introduced. However, this distinction did not exist in the original stories in their Gaelic forms. The funeral lament became a mournful cry or wail. A death in the family or one's own death was predicted upon hearing this wail or seeing the banshee. In 1437, King James I of Scotland was approached by an Irish seeress who fortold his murder by the instigation of the Earl of Atoll. That isn't the only record of banshees or prophetess in human form. There are several attending the great houses of Ireland and the courts of local Irish Kings.
A banshee's appearance differs among stories. They basically dress in white with long, fair hair which they brush with a silver comb (possibly a detail confused with mermaid myths). They have also been known to dress in green or black with a grey cloak. Although, she appears in many forms: a young woman, a stately matron, or a raddled old hag. These three forms are said to represent the triple aspects of the Celtic goddess of war and death known as Badhbh, Macha and Mor-Rioghain. She may also appear as a washer-woman, washing the blood stain clothes of those who are about to die. In that form, she is known as bean-nighe. Banshees have also been known to take animal form that of a hooded crow, stoat, hare and weasel. These animals were associated with witchcraft in Ireland.