Celtic Ireland ?

Stéphane Thibault >_

At the beginning of history, around the middle of the first millennium AD [notre emphase], the country was wholly Celtic in its language and its institutions. For linguists, this can only have come about by means of a significant immigration of Celtic-speaking people at some time in later prehistory. Such an intrusion is not, however, reflected in the archaeological evidence. There is thus seeming conflict between the two disciplines.

[…]

There is little to suggest that the earliest phase of the Irish Iron Age may be regarded as “ Celtic ”, however that term is applied. The Hallstatt culture is represented in Ireland by little more than a scatter of insular variants of the continental Gündlingen-type sword, a handful of winged chapes and a few other items […]. None of these objects is iron with the rather doubtful exception of a corroded and fragmentary sword blade from the river Shannon at Athlone for which a Hallstatt date has been claimed […].

Raftery, Barry (1996 [1995]). « Ireland. A world without the Romans », dans Miranda J. Green (dir.), The Celtic World, ch. 33, Routledge, Londres et New York, p. 637.