The north gate of Cardiff Castle, following the old Roman fortifications and rebuilt along Roman lines.

Caer (Welsh pronunciation: [kɑːɨr]; Old Welsh: cair or kair) is a placename element in Welsh meaning "stronghold", "fortress", or "citadel",[1] roughly equivalent to an Old English suffix (-ceaster) now variously written as -caster, -cester, and -chester.[2][3]

In modern Welsh orthography, caer is usually written as a prefix, although it was formerly—particularly in Latin—written as a separate word. The Breton equivalent is kêr, which is present in many Breton placenames as the prefix Ker-.


The term is thought to have derived from the Brittonic *kagro- and to be cognate with cae ("field, enclosed piece of land").[4] Although stone castles were largely introduced to Wales by the invading Normans, "caer" was and remains used to describe the settlements around some of them as well. An example is the Roman fort at Caernarfon, formerly known in Welsh as Caer Seiont from its position on the Seiont; the later Edwardian castle and its community were distinguished as Caer yn Arfon ("fort in Arfon", the latter being a district name (Cantref Arfon) from "ar Fôn", "(land) opposite Môn or Anglesey").[2] However, the modern names of the Roman fort and Edwardian castle themselves are now Segontiwm or Castell Caernarfon, while the communities carry on the name caer.

Note that the term is not believed to be related to the Irish cathair ("city"), which is instead derived from Proto-Celtic *katrixs, *catarax ("fortification").[5][6]


Gildas's account of the Saxon invasions of Britain claimed that there were 28 fortified Roman cities (Latin: civitas) on the island, without listing them.[8] The History of the Britons traditionally attributed to Nennius includes a list of the 28, all of which are called "caer".[7][12] Controversy exists over whether this list includes only Roman cities or a mixture of Roman cities and non-Roman settlements.[13] Some of the place names that have been proposed include:

Roman Britain (1911).


Caernarfon derives its name from the Edwardian Caernarfon Castle
The Roman fort now known as Segontium derived its name from a latinization of the British community along the Afon Seiont[2]

The element caer, sometimes anglicized as car, is found in several place-names in Wales such as:


The Cumbric language was spoken in Northern England until the Medieval era in which the element caer ("fort") was used in naming places.[33] It also appears in Cornish place-names as Ker-.[33]

Caer is also found in Welsh exonyms for English cities.

Carriden House, a refurbished Roman fort which formerly formed part of the Antonine Wall in Scotland.


Cumbric and Pictish were Brittonic languages spoken in Scotland until around the 12th century, and caer ("fort") was a place-naming element in both languages.[33][35]

In fiction

See also


  1. ^ Carlisle, Nicholas. Topographical Dictionary of the Dominion of Wales, "Glossary", p. xxx. W. Bulmer & Co. (London), 1811.
  2. ^ a b c Allen, Grant. "Casters and Chesters" in The Cornhill Magazine, Vol. XLV, pp. 419 ff. Smith, Elder, & Co. (London), 1882.
  3. ^ More precisely, these English placename elements derive from Latin castrum ("fortified post") and its plural form castra ("military camp"), making them the more precise equivalent of the Welsh castell.
  4. ^ Geiriadur Prifysgol Cymru, vol. 1, p. 384.
  5. ^ Ebel, Hermann Wilhelm (April 6, 2001). The Development of Celtic Linguistics, 1850-1900: Celtic studies. Taylor & Francis. ISBN 9780415226998 – via Google Books.
  6. ^ Stifter, David (June 12, 2006). Sengoidelc: Old Irish for Beginners. Syracuse University Press. ISBN 9780815630722 – via Google Books.
  7. ^ a b "JTK". "Civitas" in Celtic Culture: A Historical Encyclopedia, Vol. I, p. 451. ABC-CLIO (Sta. Barbara), 2006.
  8. ^ De Excidio Britanniae, § 3. (in Latin) Cited in the "Civitas" entry of Celtic Culture.[7]
  9. ^ a b Nennius (attrib.). Theodor Mommsen (ed.). Historia Brittonum, VI. Composed after AD 830. (in Latin) Hosted at Latin Wikisource.
  10. ^ a b c d e f g h i j k l m n o p q r s Ford, David Nash. "The 28 Cities of Britain Archived 2016-04-15 at the Wayback Machine" at Britannia. 2000.
  11. ^ a b c d e f g h i j k l m n o p q Newman, John Henry & al. Lives of the English Saints: St. German, Bishop of Auxerre, Ch. X: "Britain in 429, A. D.", p. 92. Archived 2016-03-21 at the Wayback Machine James Toovey (London), 1844.
  12. ^ Latin names according to Mommsen's edition of Nennius,[9] translations and modern equivalents according to Ford,[10] Ussher,[11] or as otherwise noted.
  13. ^ Breeze, Andrew. "Historia Brittonum" and Britain's Twenty-Eight Cities at Journal of Literary Onomastics. 2016.
  14. ^ Bishop Ussher argued for Bristol.[11]
  15. ^ Cited in Frank Reno's The Historic King Arthur: Authenticating the Celtic Hero of Post-Roman Britain, Ch. 7: "Camelot and Tintagel", p. 201.
  16. ^ Usser,[11] following John Leland.[15]
  17. ^ On page 20 of Stevenson's 1838 edition of Nennius's works.
  18. ^ Bishop Ussher cites another passage in Nennius:[17] "Here, says Nennius, Constantius the Emperor (the father probably of Constantine the Great) died; that is, near the town of Cair Segeint, or Custoient, in Carnarvonshire". Nennius stated that the emperor's inscribed tomb was still present in his day.[11] Ford credits this to Constantine, son of Saint Elen.[10]
  19. ^ Per Ford, who ascribed Nennius's "Caer-Custoeint" to one of the Dumnonian kings named Constantine.[10]
  20. ^ Although note that Bishop Ussher ascribed this to the Cambridge in Gloucestershire.[11]
  21. ^ Veprauskas, Michael. "The Problem of Caer Guorthigirn" at Vortigern Studies. 1998.
  22. ^ In Academy, Vol. XXX, Oct. 1886.
  23. ^ Henry of Huntington previously ascribed it to Lincoln, which was followed until the 19th century, when Bradley placed it at Lichfield,[22] thinking it to be the Roman Letocetum. Instead, excavations have shown that Letocetum was located at nearby Wall instead.[10]
  24. ^ Both Ussher and Ford use the transcription Lundein; with regard to Mommsen, note the similarity with Lindum, the Roman name for present-day Lincoln, and the generic name *Lindon, "lake".
  25. ^ Williams, Robert. "A History of the Parish of Llanfyllin" in Collections Historical & Archaeological Relating to Montgomeryshire, Vol. III, p. 59. J. Russell Smith (London), 1870.
  26. ^ Roman Britain Organisation. "Mediomanum?" at Roman Britain Archived 2007-04-01 at the Wayback Machine. 2010.
  27. ^ Coit is Welsh for "woods" or "forest". Ford takes the name as a single construction "Caer-Pensa-Uel-Coyt" ("Fort Penselwood"), while Mommsen and Ussher treat vel as the Latin word for or: "Cair Pensa or Coyt".[9][11]
  28. ^ Deacon, Thomas (29 May 2020). "How the suburbs of Cardiff got their names". Wales Online. Retrieved 15 May 2021.
  29. ^ a b c d e Morgan, Thomas (1912). The Place-Names of Wales (Second and revised ed.). Retrieved 16 May 2021.
  30. ^ a b "Place Names". Retrieved 15 May 2021.
  31. ^ Jones, Gwilym; Roberts, Tomos (1996). Enwau Lleoedd Môn : The Place-Names of Anglesey. Bangor, Wales: University of Wales Press. p. 122. ISBN 0-904567-71-0.
  32. ^ Owen, Hywel Wyn (15 February 2015). The Place-Names of Wales. University of Wales Press. ISBN 9781783161669. Retrieved 15 May 2021.
  33. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac James, Alan. "The Brittonic Language in the Old North" (PDF). Scottish Place Name Society.
  34. ^ A. D. Mills, A Dictionary of British Place Names (Oxford: Oxford University Press, 2011), s.v.
  35. ^ a b c d e Simon, Taylor; Markus, Gilbert (2006). The Place-names of Fife (Illustrated ed.). Shaun Tyas. ISBN 9781900289771.
  36. ^ a b c Watson, W.J.; Taylor, Simon (2011). The Celtic Place-Names of Scotland (reprint ed.). Birlinn LTD. ISBN 9781906566357.
  37. ^ a b Hall, Mark A; Driscoll, Stephen T; Geddess, Jane (11 November 2010). Pictish Progress: New Studies on Northern Britain in the Early Middle Ages. Brill. ISBN 9789004188013. Retrieved 30 June 2019.
  38. ^ "Fife Place-name Data :: Kirkcaldy".