Celtiberia, an area in present north-central Spain occupied from the 3rd century bc onward by tribes thought to be of mixed Iberian and Celtic stock. These Celtiberians inhabited the hill country between the sources of the Tagus (Tajo) and Iberus (Ebro) rivers, including most of the modern province of Soria and much of the neighbouring provinces of Guadalajara and Teruel. In historic times the Celtiberians were composed of the Arevaci, Belli, Titti, and Lusones. The earliest population of Celtiberia was that of the southeastern Almería culture of the Bronze Age, after which came Hallstatt invaders, who occupied the area shortly before 600 bc. The Hallstatt people were in turn subjugated by the Arevaci, who dominated the neighbouring Celtiberian tribes from the powerful strongholds at Okilis (modern Medinaceli) and Numantia. The Belli and the Titti were settled in the Jalón valley, the Sierra del Solorio separating them from the Lusones to the northeast.
The material culture of Celtiberia was strongly influenced by that of the Iberian people of the Ebro valley. Horse bits, daggers, and shield fittings attest the warlike nature of the Celtiberians, and one of their inventions, the two-edged Spanish sword, was later adopted by the Romans.
The Celtiberians first submitted to the Romans in 195 bc, but they were not completely under Roman domination until 133 bc, when Publius Cornelius Scipio Aemilianus destroyed Numantia. The Roman city of Clunia (Peñalba de Castro) later became the administrative centre.