Challenging the historical basis of Celtic identity is a hazardous pastime. Some have accused me of pursuing a clandestine English nationalist or racist agenda, of perpetrating 'genocide' and 'intellectual terrorism'. What generates such ferocity?
Many archaeologists specialising in the Iron Age regard the idea of ancient Celts in Britain and Ireland as an untenable, obsolete theory. This is not a deliberate attack on the identity of millions who regard themselves as Celts today, but a shift in outlook that is materially based in an explosion in the quantity and quality of evidence for the earlier societies of these islands.
Archaeology has revolutionised our understanding of the Iron Age - roughly the last 700 years BC - during which the Celts supposedly invaded or migrated from the Continent. Early archaeological work seemed to confirm this idea, revealing striking similarities between finds in Britain, Ireland and the Continent.
In recent decades, however, archaeologists have revealed unsuspected Iron Age riches of a different kind in Britain: thousands of farmsteads and entire relict landscapes of fields, paddocks and droveways, a mass of evidence for the hitherto invisible majority of late prehistoric peoples. This archaeological bonanza has overturned our conception of a 'Celtic' Iron Age.
Instead of clear evidence for "waves" of Celtic migrants, archaeology reveals a completely different picture. The (British) islands supported numerous small-scale social formations, arguably more diverse than similar to each other in social organisation, habits and ways of life. Their archaeological traces are distinctly different from those continental remains equated with the Celts of classical texts. Most significantly, the main roots of the island societies are traceable to the "indigenous" cultures of the preceding late Bronze Age. Continental connections such as 'Celtic art' are better explained in terms of exchanges between neighbours than movements of peoples.
Our picture, then, is of Iron Age Irish and British societies rooted more deeply in local prehistory than the Celtic model suggested - strongly regional groupings that were unlikely to have shared a common sense of identity.
Modern Celtic identity is very new, much newer than Welshness, Irishness or Scottishness. Such an overarching, popular self-identity is a product of the age of nation-states and romantic nationalisms, not of antiquity. Ironically, projecting Celticness back into the past obscures the complex reality of the peoples of the Iron Age.
Durham University archaeologist Simon James is author of The Atlantic Celts: Ancient People or Modern Invention? British Museum Press, 1999.