It was just a folk-memory. A story that grandmothers told to children at the fireside.

Once upon a time, so this story went, the King of Munster invaded Erris with a great army. There was a terrible battle among the sandhills and the king was killed, along with his entire army.

For centuries nothing remained to commemorate the Slaughter of Erris except for the legend and a few curious place-names in the fields and dunes of the Mullet, that slip of land in the extreme north-west of Mayo that reaches out into the cold grey sea, uncertain as to whether it belongs or not. A mound of earth in a field was Righ Mhuimnigh, the King of Munster. A nearby hollow in the dunes was Lug na Fullagh, the Hole of Blood. Nearby was a spot called the Leacht ard, the High Monument. But there was no monument. Nothing to show for the horror that was supposed to have taken place once upon a time in this remote corner of Mayo.

Then in 1811 a tremendous storm hit the coast.  When it was over, the sands had shifted, leaving behind a sea of human bones. There were bones scattered in the Hole of Blood, bones among the sandhills, and bones all round the place called Leacht ard. Stranger still, a monument had appeared. A huge conical stone cairn, 15ft high and 30ft across, was standing intact on a platform of rock where before there had been nothing but sand. It was the Leacht air Iorruis – the Monument to the Slaughter of Erris.

The Monument to the Slaughter of Erris

Every antiquarian visitor to Mayo mentioned this cairn. John O’Donovan, who helped to compile the first Irish Ordnance Survey maps in the 1830s, measured it with the help of a human shin-bone he found in the sand. The local priest excavated Righ Mhuimnigh and found a skeleton of a man standing upright, a sign that the mound was the grave of a tribal chief, perhaps even a king of Munster. T. J. Westropp, who surveyed the coast of Erris at the beginning of the twentieth century, photographed the cairn and measured it and wrote in awe of its ‘loneliness and weird surroundings, looking down to a featureless coast and unbounded sea’. By the 1940s the cairn was a recognised landmark, one of Erris’s most remarkable antiquities.

When we came here five years ago, we went looking for the Monument to the Slaughter of Erris. We knew where it was meant to be, and you’d think a 15ft-high stone cairn would be hard to miss. But could we find it? Over the years we peered at scattered stones and grassy mounds, at satellite images and ancient maps. We tramped over the dunes  and drove down rutted tracks and combed the coast. There was no sign of it.

Then the other day, all of a sudden there it was. In the middle of a farmer’s field, towering over the sandhills, looking just as it did in Westropp’s photograph and as obvious as anything could be. We knew that part of the coast so well. I still don’t understand how we missed it for so long. We had to go back a few days later to check that it hadn’t vanished, like Brigadoon.

But here’s the strange thing. Part of me is sorry. Part of me wishes those precious stones had stayed in myth and memory, forever out of reach, just as the past is always out of reach.

Part of me regrets the finding.