The Celtici (in Portuguese, Spanish, and Galician languages, Célticos) were a Celtic tribe or group of tribes of the Iberian peninsula, inhabiting three definite areas: in what today are the regions of Alentejo and the Algarve in Portugal; in the Province of Badajoz and north of Province of Huelva in Spain, in the ancient Baeturia; and along the coastal areas of Galicia. Classical authors give various accounts of the Celtici's relationships with the Gallaeci, Celtiberians and Turdetani.
Several classical sources, Greek and Roman, mentioned the Celtici.
The Celtici were not considered a barbarian people. On the contrary, they were what the Greeks considered a civilized people, almost in the same degree as the Turdetani.
Their main cities were Lacobriga (probably Lagos in the Algarve), Caepiana (in Alentejo), Braetolaeum, Miróbriga (near Santiago do Cacém), Arcobriga, Meribriga, Catraleucus, Turres, Albae and Arandis (near Castro Verde and Ourique). Other important cities were Nertobriga, Turobriga, Segida, Ebora, Caetobriga and Eburobrittium (Óbidos), among other settlements.
- Celticos a Celtiberis ex Lusitania advenisse manifestum est sacris, lingua, oppidorum vocabulis, quae cognominibus in Baetica distinguntur.
- The Celtici from Guadiana had blood links with the Galician Celts, since there had been large-scale migration to the northwest of these Celts along with the Turduli (Str., 3, 3, 5).
- ...[Pliny considers the Celtici who extend into Baetica] to have migrated from Lusitania which he appears to regard as the original seat of the whole Celtic population of the Iberian peninsula including the Celtiberians, on the ground of an identity of sacred rites, language, and names of cities.
These migratory patterns have persisted on the same axis until modern times,supporting a centuries-old traditional and seasonal farming and animal husbandry transhumance along the ancient Roman or Carthaginian Silver road that served for its rich mines production transport,and for the Astorga region peddlars and wagoneers,the Maragatos.
Pliny also noted that already in Roman times the inhabitants of Miróbriga (one of the Celtic cities of the region) used the surname of Celtici: "Mirobrigenses qui Celtici cognominantur". In the sanctuary of Miróbriga a resident leaves their Celtic origin recorded:
- D(IS) M(ANIBUS) S(ACRUM) / C(AIUS) PORCIUS SEVE/RUS MIROBRIGEN(SIS) / CELT(ICUS) ANN(ORUM) LX / H(IC) S(ITUS) E(ST) S(IT) T(IBI) T(ERRA) L(EVIS 
Traditional theories hold that the Celtici were a group that included several populi, namely the Saefes and the Cempsii, of unknown origin, which according to modern research possibly belonged to one of the first settlements of Celtic origin; and initially perhaps also the possible proto-Lusitanians (the Ligus, Lusis or Lycis), all mentioned in the Ora Maritima ("Sea Coasts") of Avienus, and possibly reinforced with subsequent waves.
According to modern research, it is now believed that "Celtici" was a collective designation given by the ancient authors to a group of Celtic-speaking tribes that inhabited the Peninsular southwest since the 5th-4th centuries BC. They were an admixture of Vaccei and early Arevaci Celtiberians who set up in upper Alentejo upon arriving from Lusitania at the mid-5th century with off-shots of three Celtic tribes originating from central and northeastern Gaul – the Bituriges, Turones, and the Belgic Eburones, which crossed the Pyrenees into the Peninsula in about 420-370 BC. Setting themselves at the ‘Mesopotamia’ region between the lower Tagus (Tajo) and middle Anas (Guadiana) rivers’ basins, the Eburones colonized most of Alentejo and part of north-western Algarve, absorbing the previous Celtiberian settlers while dominating or ousting the local Turduli and Conii populations. East of the Anas River, the bulk of the Bituriges and Turones settled mostly along its tributary, the Adrum (Ardila) river valley and the northern slopes of the Saltus Castulonensis (present-day Sierra Morena range), located in Badajoz province. In the process they either expelled or assimilated the native Elbestioi people of Ibero-Tartessian culture, and thenceforward the region became known as eastern Beturia (Beturia Celtica or Baeturia Celticorum) and its people the Baetici Celtici. Others pushed southeast into Turdetania, dispersing throughout the modern Córdoba, Seville, Cadiz, Granada, and Málaga provinces, which became known as Ultima Celtiberia, and where they founded anew or took over several autonomous Tartessian towns.
The Celtici of Alentejo and Baeturia
The main Eburones’ cities were their presumed capital Ebora (Évora), Segovia (archeological site near Campo Maior, Elvas), the coastal town of Mirobriga Celticorum (archeological site near Santiago do Cacém), and five other towns within Alentejo. Around the 3rd Century BC they managed to push southwards towards the western Algarve coast where they founded the port of Laccobriga (Monte Molião, near Lagos) in Conii territory. In Baeturia, the Bituriges set their capital at Nertobriga (Cerro del Coto, Fregenal de la Sierra – Badajoz) whilst the Turones placed theirs at Turobriga (Llanos de La Belleza, near Aroche – Huelva) and both peoples controlled six other cities.
The Celtici of Ultima Celtiberia
In Baetica the Celtici held or had a presence in some city-states, namely Celti (Peñaflor – Seville), Urso (Osuna – Seville), Obulco/Obulcula (Castillo de la Monclova, Fuentes de Andalucía – Seville; Iberian-type mint: Ipolca), Tribola (Baena – Córdoba), Munda (Montilla? – Córdoba), Tucci/Itucci (Los Martos, near Jaén – Córdoba), Turobriga (Turón – Granada), Cartima (Cártama – Málaga), Arunda (Ronda – Málaga) and Acinipo (Ronda la Vieja – Málaga).
The Celtici of Gallaecia
In the North, in Gallaecia, another group of Celtici dwelt the coastal areas. They comprised several populi, including the Celtici proper: the Praestamarci south of the Tambre river (Tamaris), the Supertamarci north of it, and the Neri by the Celtic promontory (Promunturium Celticum), whom Strabo considered related to the Celtici of Lusitania, settled in Gallaecia after a military campaign held jointly with the Turduli Veteres. Pomponius Mela affirmed that all the inhabitants of the coastal regions, from the bays of southern Gallaecia and up to the Astures, were also Celtici: "All (this coast) is inhabited by the Celtici, except from the Douro river to the bays, where the Grovi dwelt (…) In the north coast first there are the Artabri, still of the Celtic people (Celticae gentis), and after them the Astures." He also mentioned the fabulous isles of tin, the Cassiterides, as situated among these Celtici.
The Celtici Supertarmarci have also left a number of inscriptions, as the Celtici Flavienses did. Several villages and rural parishes still bear the name Céltigos (from Latin Celticos) in Galicia. This is also the name of an archpriesthood of the Catholic Church, a division of the archbishopric of Santiago de Compostela, encompassing part of the lands attributed to the Celtici Supertamarci by ancient authors.
Archaeology confirms that the material culture of the southwestern Celtici was deeply influenced by the Arevaci of Celtiberia and beyond, as their metalwork shows strong parallels with south-central Gaul, Liguria, Etruria, and central Italy. The Baetic Celtici soon fell under the cultural influence of their Iberian Turdetani neighbors, as well as receiving Hellenistic elements from the Carthaginians.
Submitted to Carthaginian rule just prior to the 2nd Punic War, the Celtici of Alentejo and Beturia recovered their independence in 206 BC whereas their Baetic counterparts simply shifted their allegiance from Carthage to the Roman Republic. In 197 BC the Ultima Celtiberia was included in the new Hispania Ulterior Province, though they were only conquered by the Ulterior Praetor Tiberius Gracchus the Elder in 179 BC. The Beturian Celtici tribes however, rose in support of a Turdetanian rebellion soon afterwards, and allied with the Lusitani and Vettones, promptly began to raid the lands of the Roman Spanish allies in Baetica and the Cyneticum throughout the 2nd Century BC. They proved to be the most reliable allies of the Lusitani – whose chieftain Viriathus used western Beturia as a rear base for its military operations on the south – in deep contrast to the Celtici city-states of Baetica, who frequently changed sides according to circumstances. When the tide turned against the Lusitani in 141 BC, the Beturian Celtici were subjected to the punitive campaigns conducted in the Iberian southwest by Consul Quintus Fabius Maximus Servilianus, who invaded eastern Beturia and plundered five towns allied with Viriathus.
- The Celts in Iberia: An Overview
- Philip Baldi; Pietro U. Dini; Villar (2004). "The Celtic Language of the Iberian Peninsula". Studies in Baltic and Indo-European Linguistics: In Honor of William R. Schmalstieg. John Benjamins Publishing. pp. 247–. ISBN 1-58811-584-4. Retrieved 27 August 2015.
- C. PLINII NATVRALIS HISTORIAE LIBER III
- Sir William Smith (1854), Dictionary of Greek and Roman geography, Volume 2, Boston, Little, Brown and Company.
- http://revistas.ucm.es/index.php/GERI/article/viewFile/GERI8888220019A/14757.pdf Breve noticia sobre o santuário campestre romano de Miróbriga dos Célticos (in Portuguese)
- The Celts in Portugal, Teresa Júdice Gamito, University of Algarve, Volume 6 / The Celts in the Iberian Peninsula - E-Keltoi, Center for Celtic Studies, University of Wisconsin-Milwaukee, 2008 
- Alarcão, Jorge. Populi, Castella and Gentilitates. Guimarães magazine. Special volume I, Guimarães, 1999. Casa de Sarmento.
- Pliny the Elder, Naturalis Historia, III, 13.
- Livy, Ad Urbe Condita, 40, 47.
- Berrocal-Rangel, Los pueblos célticos del soroeste de la Península Ibérica (1992), pp. 66-68.
- Celtici: Pomponius Mela and Pliny; Κελτικοί: Strabo
- 'Totam Celtici colunt, sed a Durio ad flexum Grovi, fluuntque per eos Avo, Celadus, Nebis, Minius et cui oblivionis cognomen est Limia. Flexus ipse Lambriacam urbem amplexus recipit fluvios Laeron et Ullam. Partem quae prominet Praesamarchi habitant, perque eos Tamaris et Sars flumina non longe orta decurrunt, Tamaris secundum Ebora portum, Sars iuxta turrem Augusti titulo memorabilem. Cetera super Tamarici Nerique incolunt in eo tractu ultimi. Hactenus enim ad occidentem versa litora pertinent. Deinde ad septentriones toto latere terra convertitur a Celtico promunturio ad Pyrenaeum usque. Perpetua eius ora, nisi ubi modici recessus ac parva promunturia sunt, ad Cantabros paene recta est. In ea primum Artabri sunt etiamnum Celticae gentis, deinde Astyres.', Pomponius Mela, De Chorographia, III, 7-9.
- Pomponius Mela, De Chorographia, III, 40.
- Eburia / Calveni f(ilia) / Celtica / Sup(ertamarca) |(castello?) / Lubri; Fusca Co/edi f(ilia) Celti/ca Superta(marca) / |(castello) Blaniobr/i; Apana Ambo/lli f(ilia) Celtica / Supertam(arca) / Maiobri; Clarinu/s Clari f(ilius) Celticus Su/pertama(ricus). Cf. Epigraphik-Datenbank Clauss / Slaby.
- [Do]quirus Doci f(ilius) / [Ce]lticoflavien(sis); Cassius Vegetus / Celti Flaviensis.
- Álvarez, Rosario, Francisco Dubert García, Xulio Sousa Fernández (ed.) (2006). Lingua e territorio (PDF). Santiago de Compostela: Consello da Cultura Galega. pp. 98–99. ISBN 84-96530-20-5.
- Livy, Ad Urbe Condita, 33: 21, 6.
- Diodorus Siculus, Bibliothekes Istorikes, 33, 7, 4-7.
- Appian, Iberiké, 68.
- History of Portugal
- History of Spain
- Prehistoric Iberia
- Pre-Roman peoples of the Iberian Peninsula
- Names of the Celts
- List of Celtic place names in Portugal
- "Tartessian" or Southwestern language ("South-Lusitanian" language)
- Ángel Montenegro et alii, Historia de España 2 - colonizaciones y formación de los pueblos prerromanos (1200-218 a.C), Editorial Gredos, Madrid (1989) ISBN 84-249-1386-8
- Mattoso, José (dir.), História de Portugal. Primeiro Volume: Antes de Portugal, Lisboa, Círculo de Leitores, 1992. (in Portuguese)
- Berrocal-Rangel, Luis (2005). "The Celts of the Southwestern Iberian Peninsula". E-Keltoi: Journal of Interdisciplinary Celtic Studies 6: 481–96.
- Luis Berrocal-Rangel, Los pueblos célticos del soroeste de la Península Ibérica, Editorial Complutense, Madrid (1992) ISBN 84-7491-447-7
- Pliny the Elder, Natural history III, 13-14.
- Alberto Lorrio J. Alvarado, Los Celtíberos, Universidad Complutense de Madrid, Murcia (1997) ISBN 84-7908-335-2
- Francisco Burillo Mozota, Los Celtíberos, etnias y estados, Crítica, Barcelona (1998, revised edition 2007) ISBN 84-7423-891-9