Before that intervention, nobody looking at Mullaghglassan Lough would have known there was anything unusual beneath the surface. The drainage work exposed what turned out to be a crannog, an artificial or partly artificial island of the kind built in Irish and Scottish lakes from the Bronze Age through to the early modern period, typically as defensible homesteads. This one has remained above the waterline ever since, a quiet accident of land management that turned into an accidental piece of archaeology.

The crannog at Maghery is modest in scale, roughly fourteen metres across and less than a metre high, and when it emerged it showed no obvious structural features, no timber framing, no evidence of dwellings. The exposed top surface was already eroded, and it became clear that the mound had been raised on a natural shoal rather than constructed from scratch in open water. What it once held, who built it, and when, the available evidence does not say. What the same drainage operation did produce, however, was something rather more dramatic: a large portion of the skeleton of a Giant Irish Deer, recovered from the lake bed nearby. That species, Megaloceros giganteus, with its extraordinary spanning antlers, vanished from the Irish landscape around ten thousand years ago, and its bones turn up periodically in bogland and lake sediments across the country. The conjunction of a prehistoric deer skeleton and a man-made island in the same body of water is the kind of detail that resists easy explanation and invites quiet curiosity.