In common with people living all over Great Britain, over the following centuries the people living in what was to become known as Wales assimilated immigrants and exchanged ideas of the Bronze Age and Iron Age Celtic cultures. Koch and others, Wales in the Late Bronze Age was part of a maritime trading-networked culture that also included the other Celtic nations, England, France, Spain and Portugal where Celtic languages developed.The Roman conquest of Wales began in AD 48 and took 30 years to complete. The campaigns of conquest are the most widely known feature of Wales during the Roman era, because of the spirited, but ultimately unsuccessful, defence of their homelands by two native tribes: the Silures and the Ordovices.Doggerland was submerged by the North Sea and, by 8,000 BP, the British Peninsula had become an island.John Davies has theorised that the story of Cantre'r Gwaelod's drowning and tales in the Mabinogion, of the waters between Wales and Ireland being narrower and shallower, may be distant folk memories of this time.Rugby union is seen as a symbol of Welsh identity and an expression of national consciousness.
Two-thirds of the population live in south Wales, mainly in and around Cardiff (the capital), Swansea and Newport, and in the nearby valleys.
Cornwall) and places in Anglo-Saxon territory associated with Celtic Britons (e.g.
Walworth in County Durham and Walton in West Yorkshire), The use of the word Cymry as a self-designation derives from the location in the post-Roman Era (after the arrival of the Anglo-Saxons) of the Welsh (Brythonic-speaking) people in modern Wales as well as in northern England and southern Scotland ("Yr Hen Ogledd") (English: In particular, the term was not applied to the Cornish or the Breton peoples, who are of similar heritage, culture, and language to the Welsh.
At that time sea levels were much lower than today, and the shallower parts of what is now the North Sea were dry land.
The east coast of present day England and the coasts of present day Denmark, Germany and the Netherlands were connected by the former landmass known as Doggerland, forming the British Peninsula on the European mainland.