Banshee

is the modern name for the bean sidhe (woman of the fairies), the traditional fairy of the IRish countryside.  After the arrival of the Milesians from what is now Spain (the ancestors of the present day Irish) the gods and goddesses known as the Tuatha De Danann disappeared underground and dwelt in mounds, and over the centuries they were slowly transformed in the popular imagination into fairies.  It was believed that the wailing of a banshee foretold the approach of a human death.