Celtic Britons

The Britons (reconstructedP-Celtic *Pritanī, Latin: Britanni, Welsh: Brythoniaid), also known as Celtic Britons or ancient Britons, were the Celtic people who inhabited Great Britain from at least the British Iron Age until the High Middle Ages, at which point they diverged into the Welsh, Cornish, and Bretons (among others). They spoke Common Brittonic, the ancestor of the modern Brittonic languages.

The oldest written evidence for the Britons is from Greco-Roman writers in the Iron Age. The earliest known mention is by Pytheas (c. 320 BC), who refers to the Pretanoi as being Keltoi (Celts). Although later Greco-Roman writers do not call them Celts, they spoke a Celtic language and had Celtic cultural traits. Ancient Britain was made up of many tribes and kingdoms, associated with various hillforts. The Britons followed an ancient Celtic religion overseen by druids. Some of the southern polities had strong links with mainland Europe, especially with Gaul and Belgica, and minted their own coins.

The Roman Empireconquered most of Britain in the 1st century AD, creating the province of Britannia. The Romans invaded northern Britain, but tribes such as the Caledonians(Picts) in the north remained unconquered, and Hadrian's Wall (which bisects the modern English counties of Northumberland and Cumbria) became the western edge of the empire. A Romano-British culture emerged, mainly in the southeast, and British Latin coexisted with Brittonic. It is unclear what relationship the Britons had with the Picts, who lived outside of the empire beyond the Firth of Forth in northern Britain; however, most scholars today accept that the Pictish language was related to Common Brittonic, being either itself a Brittonic language, or a related branch of P-Celtic, known as Pritenic.

Following the end of Roman rule in Britain during the 5th century, Anglo-Saxon settlement of eastern and southern Britain began. The culture and language of the Britons gradually fragmented, and much of their territory gradually became Anglo-Saxon, while the north and the Isle of Man became subject to a similar gradual settlement by Gaelic-speaking tribes from Ireland who would eventually form Scotland. The extent to which this cultural change was accompanied by wholesale population changes is still debated. During this time, Britons migrated to mainland Europe and established significant colonies in Brittany (now part of France), the Channel Islands, and Britonia (now part of Galicia, Spain). By the 11th century, Brittonic-speaking populations had split into distinct groups: the Welsh in Wales, the Cornish in Cornwall, the Bretons in Brittany, the Cumbrians of the Hen Ogledd ("Old North") in modern southern Scotland and northern England, and the remnants of the Pictish people in northern Scotland. Common Brittonic developed into the distinct Brittonic languages: Welsh, Cumbric, Cornish and Breton.