Ériu: Ireland's Divine Namesake by E L Hunter

A woman waits on a hill at the centre of an island, watching an army come to take her country. She will lose, and she knows it. She asks the invaders for one thing only: that whatever else they do, the land will keep her name.

They give their word. The island is called Éire to this day, after the goddess Ériu who bargained for it, and her name is written into its constitution and printed inside every passport its people carry. Yet of the goddess herself almost nothing survives. A name, a bargain on a hill, a single night with a golden stranger from the sea, and then silence. That silence is where this book begins.

What it finds is stranger than the legend. There was no secret pagan faith handed down unbroken from the Iron Age, and the beloved Triple Goddess is younger than the motor car. What there is instead is a country that has never stopped picturing itself as a woman, and has remade her in every age, from the hag who turns beautiful for the rightful king to the mother who sends her sons to die for her.

Ériu is a goddess no one prays to now. She is still the name Ireland answers to.