Before the seventh century there were three main North British kingdoms: Gododdin, Rheged and another centred on Dumbarton rock. They are called ‘North British’ mainly because Welsh texts and compositions usually refer to the P-Celtic speaking inhabitants of these three kingdoms as Gwyr y Gogledd (men of the North). Essentially, these three North British kingdoms covered all the territory stretching from the Forth-Clyde line in central Scotland to southern Yorkshire . Gododdin probably originally comprised all of Lothian and Northumberland and the boundaries of Rheged at their greatest extent may have stretched from Rochdale in Yorkshire to north Ayrshire. The borders of the kingdom based on Dumbarton rock are more complex during this period. In Gaelic and Welsh texts relating to the period before 872 AD, kings of Dumbarton rock are never given a wide territorial designation. They are always referred to as kings of “the rock of the Clyde “.
By the mid-seventh century two of these kingdoms, Rheged and Gododdin, had been absorbed into the Anglo-Saxon kingdom of Northumbria , probably by a combination of military superiority and inter-marriage between ruling dynasties. When king Ecgfrith of Northumbria was defeated by the Picts at Nechtanesmere in 685 AD, Northumbrian bishoprics had already been established at Abercorn on the Forth estuary and at Whithorn in Galloway . Only the North British kingdom based on Dumbarton rock seems to have survived until 870 AD when the fortress was destroyed by two Norse kings after a four month siege.
There is some evidence to indicate that the king of Pictland, Causantín mac Cináeda (Constantine I) – son of Cináed mac Alpín (Kenneth I) – may have been involved in the death of Arthgal, the ruling king of Dumbarton, in 872 AD. A relatively late Gaelic source states that one of Causantín’s sisters was married into the ruling Dumbarton kindred. If this information is accurate, the events of 872 AD may represent a Pictish coup by which her husband, Rhun, became king of the North Britons of Dumbarton. It is noticeable that the name of the kingdom also changes in 872 AD (to Strathclyde) and it is possible that Govan, which has a remarkable collection of sculptured stones, may have become the new sacral centre of the kingdom after this date. The last king of Strathclyde, Owen the Bald, died c.1018 AD at the battle of Carham; thereafter, the kingdom seems to have been absorbed by the king of Scots.
Scholars are extremely fortunate that a number of panegyric (praise) compositions relating to people and events in the North British kingdoms during the late sixth and early seventh centuries have been preserved in medieval Welsh texts. Although now available in written form, these compositions by two professional poets, Taliesin and Aneirin, were originally designed to be transmitted orally. Taliesin would seem to have been mainly associated with the kingdom of Rheged , Aneirin with Gododdin. Aneirin’s only surviving work, Y Gododdin (The Gododdin), is a long composition where each stanza praises the warlike abilities of individual warriors. Essentially, the whole composition relates the story of a warband setting out from a fortress on Edinburgh rock to fight an enemy force in the South, probably Anglo-Saxons. Many of Taliesin’s twelve surviving compositions praise one particular king of Rheged, Urien, and the close nature of the relationship between king and poet is highlighted by a refrain which appears at the end of seven of Taliesin’s compositions: “And until I die, old, By death’s strict demand, I shall not be joyful, Unless I praise Urien.”