There is a lake in the north of Munster which contains two islands, one rather large and the other rather small. The larger has a church venerated from the earliest times. The smaller has a chapel cared for most devotedly by a few celibates called “heaven-worshippers” or “god-worshippers.” No woman or animal of the female sex could ever enter the larger island without dying immediately. This has been proved many times by instances of dogs and cats and other animals of the female sex. When brought there often to make a trial, they immediately died. A remarkable thing about the birds there is that, while the males settle on the bushes everywhere throughout the island, the females fly over and leave their mates there and, as if they were fully conscious of its peculiar power, avoid the island like a plague. In the smaller island no one ever died or could die a natural death. Accordingly it is called the island of the living. Nevertheless the inhabitants sometimes suffer mortal sicknesses and endure the agony almost to their last gasp. When there is no hope left; when they feel that they have not a spark of life left; when as the strength decreases they are eventually so distressed that they prefer to die in death than drag out a life of death, they get themselves finally transported in a boat to the larger island, and, as soon as they touch ground there, they give up the ghost.

—Gerald of Wales, The History and Topography of Ireland (1188) (John J. O’Meara, trans.)

“I protest solemnly that I have put down nothing in this book the truth of which I have not found out either by the testimony of my own eyes, or that of reliable men found worthy of credence and coming from the districts in which the events took place,” Gerald says.

The map from the book shows Europe, Great Britain, Ireland (Hibernia), and Iceland; north is on the left.