The early Middle Ages saw the creation and adoption of the modern Welsh name for themselves, Cymry, a word descended from the Brythonic combrogi, meaning "fellow-countrymen". It appears in Moliant Cadwallon (English: In Praise of Cadwallon), a poem written by Cadwallon ap Cadfan's bard Afan Ferddig c. 633, and probably came into use a self-description before the seventh century. Historically the word applies to both the Welsh and the Brythonic-speaking peoples of northern England and southern Scotland, the peoples of the "Old North", and emphasises a perception that the Welsh and the "Men of the North" were one people, exclusive of all others. Universal acceptance of the term as the preferred written one came slowly in Wales, eventually supplanting the earlier Brython or Brittones. The term was not applied to the Cornish or the Breton peoples, who share a similar heritage, culture and language with the Welsh and the Men of the North.
All of the Cymry shared a similar language, culture and heritage. Their histories are stories of warrior kings waging war, and they are intertwined in a way that is independent of physical location, in no way dissimilar to the way that the histories of neighboring Gwynedd and Powys are intertwined. Kings of Gwynedd campaigned against Brythonic opponents in the north. Sometimes the kings of different kingdoms acted in concert, as is told in the literary Y Gododdin. Much of the early Welsh poetry and literature was written in the Old North by northern Cymry.
All of the northern kingdoms and people were eventually absorbed into the kingdoms of England and Scotland, and their histories are now mostly a footnote in the histories of those later kingdoms, though vestiges of the Cymry past are occasionally visible. In Scotland the fragmentary remains of the Laws of the Bretts and Scotts show Brythonic influence, and some of these were copied into the Regiam Majestatem, the oldest surviving written digest of Scots law, where can be found the 'galnes' (galanas) that is familiar to Welsh law.
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