Celts (ˈkelts), see names of the Celts; the most common academic usage is with a hard "c", pronounced as "k"), is a modern term used to describe any of the European peoples who spoke, or speak, a Celtic language. (Celtic Culture : A Historical Encyclopedia ISBN 978-1851094400) The term is also used in a wider sense to describe the modern descendants of those peoples, notably those who participate in a Celtic culture.
The historical Celts were a diverse group of tribal societies in Iron Age Europe. Proto-Celtic culture formed in the Early Iron Age in Central Europe's Hallstatt period, named for the site in present-day Austria). By the later Iron Age (La Tène]] period), Celts had expanded over a wide range of lands: as far west as Ireland and the Iberian Peninsula, as far east as Galatia (central Anatolia), and as far north as Scotland.
The earliest direct attestation of a Celtic language are the Lepontic inscriptions, beginning from the 6th century BC. Continental Celtic languages are attested only in inscriptions and place-names. Insular Celtic is attested from about the fourth century AD in ogham inscriptions. Literary tradition begins with Old Irish from about the eighth century. Coherent texts of Early Irish literature, such as the Táin Bó Cúailnge, survive in 12th century recensions.
By the early first milennium AD, following the expansion of the Roman Empire and the Great Migrations (Migration Period) of Germanic peoples, Celtic culture had become restricted to the British Isles (Insular Celtic), and the Continental Celtic languages ceased to be widely used by the sixth century. "Celtic Europe" today refers to the lands surrounding the Irish Sea, as well as Cornwall and Brittany on either side of the English Channel.
- Thomas M. Charles-Edwards, "Beyond empire II: Christianities of the Celtic peoples," in Cambridge History of Christianity. Vol. 3. Early Medieval Christianities, c.600–c.1100. Edited by Thomas F. X. Noble and Julia M. H. Smith. Cambridge, Cambridge University Press, 2008 (Cambridge History of Christianity), 86-106.
- Alberro, Manuel and Arnold, Bettina (eds.), e-Keltoi: Journal of Interdisciplinary Celtic Studies, Volume 6: The Celts in the Iberian Peninsula, University of Wisconsin - Milwaukee, Center for Celtic Studies, 2005.
- Collis, John. The Celts: Origins, Myths and Inventions. Stroud: Tempus Publishing, 2003. ISBN 0-7524-2913-2. Historiography of Celtic studies.
- Cunliffe, Barry. The Ancient Celts. Oxford: Oxford University Press, 1997. ISBN 0-19-815010-5.
- Cunliffe, Barry. Iron Age Britain. London: Batsford, 2004. ISBN 0-7134-8839-5
- Cunliffe, Barry. The Celts: A Very Short Introduction. 2003
- Freeman, Philip Mitchell The earliest classical sources on the Celts: A linguistic and historical study. Diss. Harvard University, 1994. (link)
- Gamito, Teresa J. The Celts in Portugal. In E-Keltoi, Journal of Interdisciplinary Celtic Studies, vol. 6. 2005.
- Haywood. Historical Atlas of the Celtic World. 2001.
- James, Simon. Exploring the World of the Celts 1993.
- James, Simon. The Atlantic Celts - Ancient People Or Modern Invention? Madison: University of Wisconsin Press, August 1999. ISBN 0-299-16674-0.
- James, Simon & Rigby, Valerie. Britain and the Celtic Iron Age. London: British Museum Press, 1997. ISBN 0-7141-2306-4.
- Kruta, V., O. Frey, Barry Raftery and M. Szabo. eds. The Celts. New York: Thames & Hudson, 1991. ISBN 0-8478-2193-5. A translation of Les Celtes: Histoire et Dictionnaire 2000.
- Laing, Lloyd. The Archaeology of Late Celtic Britain and Ireland c. 400–1200 AD. London: Methuen, 1975. ISBN 0-416-82360-2
- Laing, Lloyd and Jenifer Laing. Art of the Celts, London: Thames and Hudson, 1992 ISBN 0-500-20256-7
- MacKillop, James. A Dictionary of Celtic Mythology. Oxford: Oxford University Press, 1998. ISBN 0-19-280120-1
- McEvedy, Colin. The Penguin Atlas of Ancient History. New York: Penguin, 1985. ISBN 0-14-070832-4
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- O'Rahilly, T. F. Early Irish History Dublin Institute for Advanced Studies, 1946.
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- Ancient Celtic music - in the Citizendium
- Essays on Celtiberian topics - in e-Keltoi, University of Wisconsin, Madison
- An interactive map showing the lands of the Celts between 800BC and 305AD.
- Detailed map of the Pre-Roman Peoples of Iberia (around 200 BC), showing the Celtic territories
- Map of Celtic lands
- "The Celts" - part of Lost Treasures of the Ancient World, Cromwell Productions, 2000.
- Discussion - with academician Barry Cunliffe, on BBC Radio 4's In Our Time, February 21, 2002. (Streaming Realplayer format)
- "The Primitive Celts" - part of Terry Jones' Barbarians, June 2006.
- Gael Order, group of study and cultural heritage
- XIII. International Congress of Celtic Studies in Bonn