A little prehistory:
the Atlantic longue durée
We have seen that the Classical writers, in so far as they gave any precision at all, regarded the Celts as among the westernmost peoples of Europe. Herodotus is quite explicit about this, implying that only the Cynetes, on the western coast of Portugal, lay between them and the ocean. The Celts of Gaul were also an ocean-facing people. On this Julius Caesar is quite clear, telling us, in the famous opening paragraph of his De bello gallico, that ‘the Celts are separated from Aquitani by the river Garonne, and from the Belgae by the Marne and Seine’. The language spoken across this swathe of Gaul had close similarities to that spoken throughout much of central and western Iberia at the time and is ancestral to the ‘Celtic’ languages spoken in Brittany, Cornwall, Wales, Scotland, and Ireland in recent times. It is for all these reasons that we need to look, as dispassionately as possible, at the cultural development of western Europe throughout the longue durée of the prehistoric period.
A glance at the map of Europe, suitably adjusted to jolt our cognitive geography, is sufficient to stress that Atlantic Europe is a cohesive region. Its many promontories and peninsulas are linked by the ocean, while the flooded valleys of its ria coastlines provide sheltered waters reaching deep inland. The great rivers of France and Iberia flowing westwards into the ocean are arteries of