sentences:  The seventh and eighth centuries were characterised by ongoing warfare by the northern and eastern Welsh kingdoms against the intruding Anglo-Saxon kingdoms of Northumbria and Mercia.That era of struggle saw the Welsh adopt their modern name for themselves, "Cymry", meaning "fellow countrymen", and it also saw the demise of all but one of the kindred kingdoms of northern England and southern Scotland at the hands of then-ascendant Northumbria.The total area of Wales is , or 9% of the area of Great Britain.