North Britain has a specific meaning within the context of Dark Age Britain and refers to the territory between the river Humber and the Antonine Wall.
The first incursions of the Anglo-Saxons in the Sub-Roman period appear to have been in those areas along the south and south-east coasts of the island of Britain whereas the traditional date for the foundation of the Anglo-Saxon kingdom of Bernicia is as late as 547 and that kingdom probably remained little more than a coastal foothold until the reign of Aethelfrith in 597. In short the native British held out longer in the north and North Britain therefore became host to a number of Brythonic kingdoms, known to their Welsh cousins as Gwyr y Gogledd or
the 'Men of the North'.
A Literary Curiousity
All the early Welsh poetry that has survived, such as the work of Taliesin and Aneirin, comes not from Wales, but from North Britain. Amongst the works atributed to Taliesin are works in praise of of the warrior prince Cunedda, Urien Rheged and his son Owain ab Urien prince of Rheged, northern figures all. From Aneirin comes the tale of Y Gododdin, of a doomed warband coming south from the kingdom of Gododdin to do battle with the Anglo-Saxons at Catraeth. Many of the Thirteen Treasures of the Island of Britain were to be found in the north and numerous Welsh Triads refer to the kings of the north such as Rhydderch Hael.
What this illustrates is that during the immediate post Roman period from the fifth to the mid seventh century, North Britain and Wales were simply one cultural continuum.
Old King Cole
The Welsh Genealogies record the descent of many of these kings of the north, most of whom would claim descent from the figure of Coel Hen, that is 'Coel the Old', Old King Cole himself. Tradition accords this figure of Coel an important role in the history of North Britain, who is usually placed sometime in the years 380 to 420. This marks the period at which the hold of the Roman Empire over Britain was weakening and when Roman governors of Britannia such as Magnus Maximus and Constantine III had aspirations that extended beyond the confines of the island. As they persued their imperial ambitions on the continent they may well have looked to local warlords and chieftains to maintain order within the province whilst they directed their attention elsewhere.
If the genealogies are to be believed then Coel Hen was 'king of the north' and a succession of minor kingdoms were established by his sons and grandsons. On his death North Britain was divided between his two sons; Gorbanian the younger, who founded the dynasty that ruled over the kingdom of Bryneich and Ceneu the elder who ruled the rest of the north from York. When Ceneu died his kingdom was divided between his two sons, Gwrgant and Mor; with Gwrgant taking Rheged and Mor the kingdoms of Caer Ebrauc and Caer Guendoleu.
The one North British kingdom that fails to boast any dynastic link with Coel Hen is that of Strathclyde where the genuine historic figure of Ceretic Guletic appears as a founder figure in the mid fifth century.
The kingdoms of North Britain
Most of which ended up as part of Northumbria by the end of the seventh century, but Strathclyde and Gododdin eventually ended up as southern Scotland.
Other possible kingdoms (for which there is little discernible evidence are Dunoting based around the area of Dent in Yorkshire and a possible Brythonic fore-runner of the later Anglo-Saxon kingdom of Pecset in northern Derbyshire.