section_path: History/Prehistoric Ireland/Emergence of Celtic Ireland
section_name: Emergence of Celtic Ireland
paragraph_text: Emergence of Celtic Ireland
  
  How and when the island became Celtic has been debated for close to a century, with the migrations of the Celts being one of the more enduring themes of archaeological and linguistic studies. The most recent genetic research strongly associates the spread of Indo-European languages (including Celtic) through Western Europe with a people bringing a composite Beaker culture, with its arrival in Britain and Ireland dated to around the middle of the third millennium BC. According to John T. Koch and others, Ireland in the Late Bronze Age was part of a maritime trading-network culture called the Atlantic Bronze Age that also included Britain, western France and Iberia, and that this is where Celtic languages developed. This contrasts with the traditional view that their origin lies in mainland Europe with the Hallstatt culture.
  
  The long-standing traditional view is that the Celtic language, Ogham script and culture were brought to Ireland by waves of invading or migrating Celts from mainland Europe. This theory draws on the Lebor Gabála Érenn, a medieval Christian pseudo-history of Ireland, along with the presence of Celtic culture, language and artefacts found in Ireland such as Celtic bronze spears, shields, torcs and other finely crafted Celtic associated possessions. The theory holds that there were four separate Celtic invasions of Ireland. The Priteni were said to be the first, followed by the Belgae from northern Gaul and Britain. Later, Laighin tribes from Armorica (present-day Brittany) were said to have invaded Ireland and Britain more or less simultaneously. Lastly, the Milesians (Gaels) were said to have reached Ireland from either northern Iberia or southern Gaul. It was claimed that a second wave named the Euerni, belonging to the Belgae people of northern Gaul, began arriving about the sixth century BC. They were said to have given their name to the island.
  
  The theory was advanced in part because of the lack of archaeological evidence for large-scale Celtic immigration, though it is accepted that such movements are notoriously difficult to identify. Historical linguists are skeptical that this method alone could account for the absorption of Celtic language, with some saying that an assumed processual view of Celtic linguistic formation is 'an especially hazardous exercise'. Genetic lineage investigation into the area of Celtic migration to Ireland has led to findings that showed no significant differences in mitochondrial DNA between Ireland and large areas of continental Europe, in contrast to parts of the Y-chromosome pattern. When taking both into account, a study concluded that modern Celtic speakers in Ireland could be thought of as European "Atlantic Celts" showing a shared ancestry throughout the Atlantic zone from northern Iberia to western Scandinavia rather than substantially central European. In 2012, research showed that the occurrence of genetic markers for the earliest farmers was almost eliminated by Beaker-culture immigrants: they carried what was then a new Y-chromosome R1b marker, believed to have originated in Iberia about 2,500 BC. The prevalence amongst modern Irish men of this mutation is a remarkable 84%, the highest in the world, and closely matched in other populations along the Atlantic fringes down to Spain. A similar genetic replacement happened with lineages in mitochondrial DNA. This conclusion is supported by recent research carried out by the geneticist David Reich, who says: "British and Irish skeletons from the Bronze Age that followed the Beaker period had at most 10 per cent ancestry from the first farmers of these islands, with other 90 per cent from people like those associated with the Bell Beaker culture in the Netherlands." He suggests that it was Beaker users who introduced an Indo-European language, represented here by Celtic (i.e. a new language and culture introduced directly by migration and genetic replacement).