Wales, the nation-state or geographical area, is intimately connected with the people called Welsh. Peoples are generally identified by geography, kinship (however loose) and language. In this case, the geographical definition of Wales is relatively simple – as a peninsula, it has an obvious boundary formed by drawing a more-or-less straight line from an inlet of the Irish Sea near Chester, south to the Bristol Channel. The actual eastern border with England is largely as defined by the Laws in Wales Acts 1535–42, based on the boundaries of medieval Lordships of the March. It follows the defensive line called Offa’s Dyke, possibly established in the eighth century, but perhaps based on an earlier Roman structure built by Septimius Severus, Roman Emperor around 200. Offa’s Dyke separated the ancient Welsh kingdom of Powys from the Anglian kingdom of Mercia, but about 40 miles from the north coast the modern border takes a diversion to the east from this.

Strangely, the actual Welsh perimeter has never been formally confirmed by a Boundary Commission, although it is formed by the borders of the easternmost counties. There are some amusing anomalies – for example, Knighton is separated from its railway station, and in the village of Llanymynech the boundary runs straight through a pub.

Today, Wales is separated into 22 unitary areas but is thought of as having 13 historic counties. It is part of the United Kingdom of Great Britain and Northern Ireland. However, it is not a separate country (as Scotland is), but is a principality of England. Its citizens are British citizens.

The other way to define Wales is where the Welsh (Cymry) lived and live. But who are they?

The term ‘Welsh’ defines the ethnic group native to Wales and associated with the Welsh language, but even that isn’t straightforward. There was nothing that could reasonably be called a separate ‘Welsh nation’ until the Romans withdrew from Britain in the late fourth to mid-fifth centuries. They had met tribes in Wales that they called Deceangli, Demetae, Ordovices and Silures. However, these inhabitants were no different from anyone else in southern Britain – they were all Britons, speaking the common language, British. This is a Celtic tongue of the Brythonic group, which also includes Breton and Cornish. It is distinguished from the Goidelic group, comprising Irish Gaelic, Scots Gaelic and Manx. The Celtic tongue and the associated culture probably first arrived in Britain in the Late Bronze Age or Early Iron Age (around 1,200 BC), although DNA evidence suggests that this might be a cultural overlay of an Indo-European language and cultural shift onto pre-existing inhabitants.

These original inhabitants of Britain were mainly indigenous European Paleolithic (Old Stone Age) hunter gatherers, with a later and smaller Neolithic (New Stone Age) farming population. It seems, from various strands of evidence, that after the last ice age (8,000 BC) a small population survived in Iberia (present-day Spain and Portugal) and spread throughout Europe during the Mesolithic period (up to 5,000 BC). Neolithic incomers were from further east in Europe. The Welsh themselves consider themselves Celts with a heritage traced back to the Iron Age tribes, superimposed to some extent by Romano-British culture and a language that has some Latin influence.

The prototype of the Welsh language was spoken farther afield – as far north as Strathclyde and the Lothians, where it remained even after the encroachments from Ireland of the Gaelic Scotii and their Goedelic language into Argyll in the fifth and sixth centuries. It surprises many Scots that William Wallace’s native language was one cognate with Welsh, and that ‘Wallace’ itself may mean ‘Welsh’, which is from the Germanic walha and indicates ‘foreigner’ or ‘stranger’ and is much the same word as ‘Gaulish’. It also surprises many Welsh people that their great early poem, Y Gododdin, was written in the Brythonic kingdom of Gododdin, which extended from the Tyne to the area around Stirling, with its capital at Din Eidyn (Edinburgh), and which rubbed up against the genetically and linguistically distinct Picts of Fife, Angus and the Mearns (Kincardineshire).

After the Romans left, Anglo-Saxons invaded Britain and gradually pushed west, possibly wiping out a large proportion of the indigenous population and forcing the remainder west. This makes the peoples of Wessex, Wales, Cumbria, Strathclyde and Lothian the original Britons; what became the ‘English’ were Germanic invaders who undertook a form of ethnic cleansing.

But if the Welsh are the Britons, why do they not call themselves that? There is evidence of the early use of the term Brythoniaid (Britons), but the first use of Kymry (which refers to the place, not the people) is in a poem from the 630s – around the time that the Brythonic language had changed to Welsh – and may have included the northern areas listed above. That explains the name of the region known as Cumbria, and the Brythonic language used there as Cumbric. Eventually Cymru came to indicate the land now called Wales, and Cymry the people. This makes sense – if ‘Wales’ derives from the a word meaning ‘stranger’ in the Romanised world, Cymru and Cymry come from the Brythonic word combrogi, meaning ‘fellow-countrymen’, a much more comfortable term than the English words Welsh and Wales, with their implications of ‘foreign’ and ‘strange’. Modern Welsh has two words for the English: Saeson (singular Sais), originally meaning ‘Saxon’, and the less commonly used Eingl, meaning ‘Angles’. The Welsh word for the English language is Saesneg and for England is Lloegr .

Of course, there have been later overlays too, both cultural and linguistic. Scandinavians invaded (as Vikings) and settled from the ninth century, as did the Normans (North-men, themselves descended from Vikings in northern France) after 1066; both of these had a much greater influence on language than the Romans. Any traces of Latin we now find in English are echoes of the language of Rome in Norman French, imports from the medieval church into law, and ‘scholarly borrowings’ after the Renaissance. It was the Normans who had the largest direct influence on the land and people of Wales, as Anglo-Normans were given lands in Wales and encouraged to settle there. There is a so-called ‘Landsker Line’ dividing the ‘Englishry’ and ‘Welshry’ of Pembrokeshire, and similar terms are used for parts of Gower.

The term ‘Welsh’ also applies to those from Wales and of Welsh ancestry who identify themselves or are identified as sharing a cultural, linguistic, geographical and ancestral heritage (as in ‘Australian-Welsh’). Denied a chance to describe themselves as ‘Welsh’ in the 2001 census, about 14 per cent overall actually wrote on the form that they were ethnically Welsh (27 per cent in Gwynedd, 23 per cent in Carmarthenshire, 22 per cent in Ceredigion and 19 per cent in the Isle of Anglesey).The Welsh fought for the inclusion of added questions in 2011, and got: What is your country of birth? (with ‘Wales’ as an option), How would you describe your national identity? (‘Welsh’ and ‘English’ were among the options), What is your ethnic group? (‘White Welsh/English/Scottish/Northern Irish/British’ was an option) and Can you understand, speak, read or write Welsh? At the time of writing (2012), there is no analysis available.

In 2001/02 the Labour Force Survey found that 87 per cent of Wales-born residents claimed to be ethnically Welsh. (The residential population includes 30 per cent born outside Wales.) Interestingly, a separate study by Oxford University identified that 18 per cent of respondents thought of themselves as ‘Welsh and not British’, 20 per cent ‘more Welsh than British’ and 39 per cent ‘equally Welsh and British’. In general, younger people are more likely to identify themselves as ‘Welsh’ in some way. This Welsh/British distinction is at odds with history, but is indicative of the strong sense of identity that pervades what some refer to, rather dismissively, as ‘Welsh Wales’.

Speaking Welsh is a central component of Welsh identity – more than speaking Gaelic or Scots is in Scotland. The Welsh themselves speak of Cymry Cymraeg (the Welsh-speaking Welsh), Cymry di-Gymraeg (the non-Welsh-speaking Welsh) and Saeson (English, not Welsh at all).

There is no question that the number of Welsh speakers in Wales is rising – there was a time when it was actively discouraged, especially in schools. The 2001 census (see above) may not have directly enumerated those considering themselves ‘Welsh’, but it did assess language, as did that of 2011. About 20 per cent of the population (so about 600,000 out of roughly 3 million) claimed to be fluent in Welsh; a further 28 per cent claimed to understand it. The increase over the last decade is most marked in large towns such as Cardiff (Caerdydd), and in the Rhondda. Welsh speakers in Gwynedd and Ceredigion have decreased, but these areas have had the greatest influx of new, non-Welsh residents. There is also evidence that non-Welsh-speaking residents moving to rural North Wales have diluted the language base. About a quarter of Welsh residents are from outside Wales.

Welsh is the first language in much of the rural north and west (the Isle of Anglesey, Gwynedd, central Denbighshire) followed by Powys, Ceredigion and Carmarthenshire, then North Pembrokeshire and western Glamorgan. Historically, this matches the places that did not have an influx of incomers for the slate-mining, coal-mining and other industries in the 19th and 20th centuries. But there are first-language and fluent speakers all over Wales, including the urbanised south, especially now that Cardiff is home to many national organisations in the public and private sectors who need Welsh speakers.

There is hardly anyone who speaks only Welsh and almost everyone is truly bilingual in English and Welsh, but many Welsh speakers prefer to use Welsh rather than English. This also depends on the area – English is commoner in South Wales and large towns, and Welsh in North Wales and rural areas. Visitors often notice what linguistics specialists call ‘code-switching’, a shift from one language to the other depending on context, companions, presence or absence of other Welsh speakers and so on. Furthermore, because of the purposive promotion of the Welsh language, and the existence of the Welsh Assembly (with devolved but limited powers of self-government), learning and using the Welsh language is important in career and cultural openings.

The growth of interest in the language (and the use of it) since 1945 mirrors a rise in Welsh nationalism, the emergence of the political party Plaid Cymru, the increased activities of Cymdeithas yr Iaith Gymraeg (the Welsh Language Society), the existence of Welsh-only television and radio stations, road signs in Welsh and the teaching of Welsh in schools.

Meat and drink to genealogists, surnames are an important aspect of identity. Strangely (according to a survey of Welsh surnames commissioned by the Welsh Assembly) only a third of the population of Wales have a family name of Welsh origin. The equivalent figure in the rest of the UK is about 5 per cent, and not much less in New Zealand, Australia and the USA. Over 16 million people worldwide are considered to be of Welsh ancestry – probably an underestimate.

Six out of the top ten commonest surnames in Britain are Welsh. The question is, though – why is the proportion of Welsh surnames in Wales not higher?

The population of Wales grew from less than 600,000 in 1801 to almost twice that in 1851, and twice that again by 1911.This trend was common during the Industrial Revolution in Britain – death rates (especially infant mortality) fell and birth rates were stable, but migration into Wales was marked. Most immigrants were English, but Irish also figured, as did ethnic groups from elsewhere, notably Italians migrating to the South Wales coal mines.

In the 20th century, as in the rest of Britain, there has been immigration from the British Commonwealth of African-Caribbean and Asian ethnic groups, and a more recent influx from new accession countries of the European Union such as Poland.

Partly this is to do with land inheritance. In Wales, and indeed for Catholics in Ireland, unlike in England (except Kent), a man’s estate was divided equally among his sons – a custom known as ‘gavelkind’. Someone’s two sons who pass their share onto their two sons and so on could easily result in a number of unworkably small plots of land. So they left the land.

There is no particularly Welsh genetic pattern. The commonest marker is R1b (about 85 per cent) as with most Britons, who, after all, arrived from the Iberian Peninsula in the Mesolithic and the Neolithic times. Bryan Sykes in Blood of the Isles and Stephen Oppenheimer in The Origins of the British, summarise the genetic evidence. Oppenheimer claims that 96 per cent of lineages in Llangefni (North Wales) derive ultimately from Iberia. Y-chromosome markers amongst the Welsh, as with the Irish, show a common ancestry with the Basques of northern Spain and south-western France, perhaps with more Neolithic input than these.

Timeline: Wales