Historically, the Britons (sometimes Brythons or British) were the P-Celtic speaking indigenous peoples inhabiting the island of Great Britain south of the river Forth. They were speakers of the Brythonic languages (also called P-Celtic) and shared common cultural traditions; the surviving P-Celtic languages are Welsh, Cornish and Breton. In terms of language and culture, much of north-western Europe was mainly Celtic during this period. The inhabitants of Ireland, the Isle of Man and Dál Riata were Gaels or Gaelic Celts who spoke Goidelic languages.

A number of scholars argue that the unknown Pictish language was Brythonic, but in Sub-Roman Britain the Picts were distinguished as a separate group, as were the Gaels of Dál Riata. Therefore, the term "Briton" traditionally refers to the inhabitants of ancient Britain excluding the Picts, because many Pictish cultural traits (for example their sculpture, pottery and monuments) differ from those of the Britons and because ancient writers clearly distinguish the two peoples.

Britons -  Wikipedia, the free encyclopedia