Lloegyr is the medieval Welsh name for a region of Britain (Prydain). The exact borders are unknown, but some modern scholars hypothesize it ran south and east of a line extending from the Humber Estuary to the Severn Estuary, exclusive of Cornwall and Devon. The people of Lloegyr were called Lloegyrwys without distinction of ethnicity, the term applying to both Britons and Anglo-Saxons.
The modern form of the word is Lloegr ( or ) and it has become generalised through the passage of time to become the Welsh word for "England" as a whole, and not restricted to its original, smaller extent. The word has been anglicised and Latinised into such forms as Logres, Logris, and Loegria, among others, and is perhaps most widely recognised as the name of King Arthur's realm in the body of literature known as the Matter of Britain. The word is known to date from the 10th century or earlier, as it appears in the literary Armes Prydein.
Welsh antiquarians of the 18th and 19th centuries hypothesized that the borders of Lloegyr ran roughly on a line from the Humber Estuary, continuing southwestwards and connecting to the Severn Estuary. The line continues south across the estuary, crossing South West England such that Cornwall and Devon are excluded from Lloegyr. The division can also be inferred from the use of the term Old North (Hen Ogledd) being the north of Cymru, separate from the south east of the island. The division is mentioned in literature (e.g., the Welsh Triads) and is supported by the works of respected historians such as John Rhys' Celtic Britain and John Edward Lloyd's A History of Wales from the Earliest Times to the Edwardian Conquest.
While Geoffrey of Monmouth invented fanciful characters and places in his stories of Loegria and its eponymous king Locrinus, he also showed that he was aware that the actual boundary of Lloegyr was known to run between the Humber and Severn estuaries, and that Cornwall was distinct from Loegria.
The relationship between the Cymry and Lloegrwys in antiquity is unkown, due to the lack of written records by the Celts. There is some archeological evidence that tribes of Lloegr were slightly more urbanised and minted coins, and from their geography more connected through trade with the continent. Roman sources do not present a clear distinction between these as broad groups above local tribal relationships, however during the Roman conquest of Britain after their initial campaign of AD 43-47, they did fortify their frontier conquest along the Fosse Way (roughly the proposed border of Lloegr). Their further conquest of the west (modern day Wales) and north was not accomplished until AD 78 and AD 84 respectively.
The exact origin of the word is uncertain and has spawned a great deal of speculation. 12th century AD author Geoffrey of Monmouth offered an etymology in his Historia regum Britanniae, deriving the names of Cambria, Loegria, and Albany from the sons of Brutus of Troy: Camber, Locrinus, and Albanactus, respectively, and makes them the eponymous kings of Wales/Cambria (Camber), England/Loegria (Locrinus), and Scotland/Albany (Albanactus). In 1982, noted linguist Eric Hamp suggested that Lloeg(y)r could be derived from a Proto-Celtic compound *(p)les-okri-s, meaning 'having a nearby border, being from near the border'. Ranko Matasoviàprefers to see Lloegr as coming from a Brittonic collective noun *LÃÂikor meaning âÂÂwarriorsâÂÂ, the root of which he proposes gave Old Irish láech "warrior" (though some scholars regard the Old Irish word as a loan from Late Latin lÃÂicus âÂÂlayman; of the peopleâÂÂ), from a Proto-Indo-European root *leh<sub>2</sub>- "war". The suffix -wys found in numerous Welsh ethnic names, including Lloegrwys, is thought to possibly be derived from the Latin suffix -ÃÂnsÃÂs according to some. Richard Coates makes a suggestion which agrees semantically with MatasoviÃÂ's, but proposes instead that it is borrowed from West Germanic (i.e. pre-Old English) *laikÃÂrà Âs âÂÂperformers of exploits, players (in a military sense), warriorsâÂÂ.
Cymry is the Welsh word for themselves, and historically included all of the Britons living north and west of Lloegyr, south of the Scottish firths of Clyde and Forth, and not including the people of Cornwall and Devon.