Regarded by the Greeks and Romans as the most militaristic people of the eastern Meseta, the Arevaci were said by Herodotus to have embarked early on an expansionist policy by taking part in the Celtici migrations of the 5th century BC alongside off-shots of Lusones and Vaccaei peoples to settle in the Iberian southwest. In the late 4th-early 3rd centuries BC however, the Arevaci shifted the direction of their expansion to the east, towards the upper Duero and south into the central Iberian system mountains. Here they displaced the earlier inhabitants the Pellendones, conquering the towns of Savia and Numantia and submitted the Uraci, thus gaining control over the strategic towns of "Aregrada" (Ágreda? – Soria; Celtiberian mints: "Areicoraticos"/"Arecorataz"), "Cortona" (Medinaceli? – Soria), "Segontia" (Sigüenza – Guadalajara) and "Arcobriga" (Monreal de Ariza – Zaragoza).