The BIRM-166 Datum
Archived: 27 September 2026
Thirty thousand five hundred and sixty-two BCE is a modern chronological label, not a recoverable Irish historical year. The BIRM-166 radiocarbon date from Derryvree, County Fermanagh, falls within a calibrated range and documents an interval between glacier advances. Sediments, pollen, plants, insects and mosses indicate cold, open, treeless wetland with freshwater pools, rather than uniformly ice-covered terrain. Ireland experienced unstable Late Pleistocene climates and expanding ice sheets, with changing coastlines and uncertain routes. Castlepook Cave preserves cold-stage fauna and a butchered reindeer bone, but human presence remains unproven. Evidence therefore supports environmental reconstruction, not claims of society, settlement or politics.