The ancient round barrows called Sidhe are the domains of the Fairies. In Celtic mythology, the Tuath Dé Danann, also known by the earlier name Tuath Dé, were the ancient people of Ireland. After being defeated in battle, they made themselves invisible and went to live in the Sidhe. Today, the Tuath Dé Danann are called the Fairy folk. It's said they appear to humans at these Fairy hills on Midsummer's Eve. Their knot honors the spirit of the Fairy folk.
