Irish Iron Age

The prehistory of Ireland has been pieced together from archaeological and genetic evidence; it begins with the first evidence of humans in Ireland around 12,500 years ago and finishes with the start of the historical record around 400 AD. The prehistoric period covers the Palaeolithic, Mesolithic, Neolithic, Bronze Age and Iron Age societies of Ireland. For much of Europe, the historical record begins when the Romans invaded; as Ireland was not invaded by the Romans its historical record starts later, with the coming of Christianity.

During the most recent Quaternary glaciation, ice sheets more than 3,000 m (9,800 ft) thick scoured the landscape of Ireland, pulverising rock and bone, and eradicating any possible evidence of early human settlements during the Glenavian warm period (human remains pre-dating the last glaciation have been uncovered in the extreme south of Britain, which largely escaped the advancing ice sheets).

During the Last Glacial Maximum (ca. 26,000–19,000 years ago), Ireland was an Arctic wasteland, or tundra. The Midland General Glaciation ("Midlandian period") was originally thought to have covered two thirds of the country with ice. Subsequent evidence from the past 50 years has shown this to be untrue and recent publications (Greenwood and Clark, 2009) suggest that ice went off the southern coast of Ireland. The early part of the Holocene had a climate that was inhospitable to most European animals and plants. Human occupation was unlikely, though fishing possible.

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