Celtiberia

The Celtiberians were a group of Celts inhabiting the central-eastern Iberian Peninsula during the final centuries BC. They were explicitely mentioned as being Celts by several classic authors (e.g. Strabo). These tribes spoke the Celtiberian language and wrote it by adapting the Iberian alphabet. The numerous inscriptions discovered, some of them extensive, allowed scholars to classify the Celtiberian language as a Celtic language, possibly one of the Hispano-Celtic (also known as Iberian Celtic) languages that were spoken in pre-Roman and early Roman Iberia. Archaeologically, many elements link Celtiberians with Celts in Central Europe, but also show large differences with both the Hallstatt culture and La Tène culture.

There is no complete agreement on the exact definition of Celtiberians among classical authors, nor modern scholars. The Ebro river clearly divides the Celtiberian areas from non-Indoeuropean speaking peoples. On the other directions, the demarcation is less clear. Most scholars include the Arevaci, Pellendones, Belli, Titti and Lusones as Celtiberian tribes, and occasionally the Berones, Vaccaei, Carpetani, Olcades or Lobetani.

The term Celtiberi appears in accounts by Diodorus Siculus,Appian and Martial who recognized intermarriage between Celts and Iberians after a period of continuous warfare, though Barry Cunliffe says "this has the ring of guesswork about it."Strabo just saw the Celtiberians as a branch of the Celti.Pliny the Elder thought that the original home of the Celts in Iberia was the territory of the Celtici in the south-west, on the grounds of an identity of sacred rites, language, and the names of cities.

...
Wikipedia