The Grianán of Aileach is associated with a rich tapestry of mythology, tales and legends. One legend tells of Dagda, the king of the godly Tuatha de Dannán. His son, Aodh, was killed by a man named Coirgean, in a fit of jealousy. Instead of killing the perpetrator on the spot, Dagda placed a géis, [an unbreakable oath], on Coirgean which meant he was compelled to carry Aodh’s body until he found a flag stone big enough to cover the slaughtered god. Coirgean carried Aodh for miles, until he climbed this hill and found the right stone. He buried Aodh beneath it, and then promptly dropped dead of exhaustion. To mark the burial place of his son, Dagda had a palace constructed on the hilltop, and held fairs in celebration of Aodh’s life. From the Dindshenchas:
Cnoc arar-chotail in Dagda, dearg a scotha,
Imda a thige, terc a chrecha, cert a cloche
Hill where the Dagda slept, red are its flowers,
many its houses, few its plunderings, correct its stones.
A tale from the National Folklore Collection tells of a man who was on the run from English soldiers. He sought to escape by climbing the steep slopes of the Grianán of Aileach, but he saw the soldiers had the hill surrounded and that he was trapped. In desperation, he looked around for a place to hide and noticed a small doorway which he had never seen before. The door was ajar and a passageway behind it appeared to lead into the side of the hill. With the soldiers closing in, the man had no choice but to venture down the passageway. He closed the door behind him, and outside he could hear the confused soldiers searching for him, then angrily leaving the hill empty-handed. But rather than taking a risk by going back outside, he chose to follow a dim light and venture deeper down the dark passageway.
As he walked along the passage the light grew steadily stronger, until he came out into a large hall where he saw a king sleeping on a chair, flanked by his court and bards, and with thousands of warriors all slumbering around him. He implored the slumbering host to rise up and to attack the English. At the sound of his voice, the strange king opened his eyes and said “the time has not yet come” and went to sleep again. It is said they still slumber under the hill, until a day when a woman lights four fires, one north, one south, one east and one west and the final one on Mount Errigal. Then she must sound a great horn on Aileach. As the note ends seven doors will open in the ground and the host will charge from the side of the hill, where they will race around the country to set Ireland free.