A number of historians of Wales have questioned the notion of a single, cohesive Welsh identity.
For example, in 1921, Alfred Zimmern, the inaugural professor of international relations at the University of Wales, Aberystwyth, argued that there was "not one Wales, but three": archetypal 'Welsh Wales', industrial or 'American Wales', and upper-class 'English Wales'. Each represented different parts of the country and different traditions.
In 1985, political analyst Dennis Balsom proposed a similar 'Three Wales model'. Balsom's regions were the Welsh-speaking heartland of the north and west, Y Fro Gymraeg; a consciously Welsh but not Welsh-speaking 'Welsh Wales' in the South Wales Valleys and a more ambivalent 'British Wales' making up the remainder, largely in the east and along the south coast. The division reflects, broadly, the areas where Plaid Cymru, Labour, and the Conservatives and Liberal Democrats respectively enjoyed the most political support.
Topography has traditionally limited the integration between North and South Wales, with the two halves virtually functioning as separate economic and social units in the preindustrial era. Even today, the main road and rail links run east-west. By the interwar years, industry in South Wales was increasingly linked to Avonside and the English Midlands, and that in north Wales to Merseyside.
Liverpool was often called "the capital of north Wales" in the late 19th and early 20th century. With 20,000 Welsh-born people living on either side of the Mersey in 1901, the city had an array of Welsh chapels and cultural institutions; hosted the National Eisteddfod in 1884, 1900 and 1929 and gave rise to several leading figures in Welsh life in the 20th century. The Liverpool Daily Post became, effectively, the daily newspaper for north Wales. The decline of Liverpool after the Second World War and changing patterns of Welsh migration, caused the Welsh presence to diminish. In the 1960s, the flooding of the Tryweryn Valley to provide the city with water soured relations with many people in Wales.
North Walians are called, in Welsh, Gogs (from the Welsh gogledd, "north") and south Walians Hwntws (from "tu hwnt" roughly meaning 'far away over there' or 'beyond'). There are differences in the Welsh vocabulary between the north and south; for instance, the south Walian word for "now" is nawr whereas the north Walian is rwan.
The more urbanised south, containing cities such as Cardiff, Newport and Swansea, was historically home to the coal and steel industries. It contrasts with the mostly rural north, where agriculture and slate quarrying were the main industries. Although the M4 corridor brings wealth into South Wales, particularly Cardiff, there is no pronounced economic divide between north and south unlike in England; there is, for example, a high level of poverty in the postindustrial South Wales Valleys.