Ireland’s landscape is dotted with remnants from earlier inhabits of the isle. Evidence has been found of human activity 8000 years ago from a hunter-gatherer settlement in Ireland and there may be earlier evidence still for human occupation. [ref] https://www.bbc.com/news/science-environment-35863186 [/ref] So even to someone living in the middle ages, there would have been thousands of generations of people who had inhabited the landscape before.
Without access to the tools of modern day archeology, what were people supposed to think of these distant signs of people before them?
Ireland is littered with the remnants of old ringforts. These were fortifications used during the iron and bronze ages, up to around 1000 AD. Circular in structure, they consisted of a raised hill surrounded by a wooden palisade with ditches around the outside. [ref] https://www.irishtimes.com/culture/heritage/fairy-forts-why-these-sacred-places-deserve-our-respect-1.3181259 [/ref] A small ringfort would be used by a farmer to protect his family and his lifestock, while a chieftan would have a huge ringfort to protect a village.
Now all that can be seen of these long ago defenses are contoured circular rises. They are covered in grass, but are too prominent to be dismissed as naturally occurring. To a people far distanced from the original occupants, these strange hills were explained away as the homes of the fairies.
Fairies in Ireland are a bit different to the ones portrayed as living at the bottom of your garden. Those small, polite beings are seem almost like butterflies, but with a genteel, tiny person in the middle where the insect bits are normally. The Irish fairies, also known as Aos Si, are mysterious. Their motivations are not able to be discerned. They dwell in another realm that runs parallel to ours and their mysterious fairy forts lead to halls and palaces.
It is easy to see how a rich, complex mythology could develop. All around were signs of other occupants of the land, but not a people that could instantly be related to. The fairy forts may appear in out of the way places, but such places may have been strategic outpost hundreds of years ago.
There was and still is the belief that disturbing a fairy mound would bring terrible curses upon oneself. It’s the reason there are 45,000 fairy forts still surviving in Ireland today.[ref] https://www.irishtimes.com/culture/heritage/fairy-forts-why-these-sacred-places-deserve-our-respect-1.3181259 [/ref] Even if they are not the home to a supernatural race, the remnants of the ringforts are still a connection to a people who lived in a very different time, under very different circumstances.
