At the beginning of the Christian Era, dialects of Euskarian (Basque) stock were probably spoken north and south of the Pyrenees and as far east as the Valle de Arán in northeastern Spain. It is likely that only the disruption of Roman administration in these regions saved the Basque dialects from being completely overcome by Latin. It is also likely that the Basque tongue, which had a firm foothold in the country that then began to be called Vasconia, experienced a substantial expansion toward the southwest, which carried it to the Rioja Alta (High Rioja) region in Old Castile and near Burgos. The more eastern Basque dialects, separated from the main area by Romance-speaking populations, were doomed. During the Middle Ages, Basque, the language of a population more peasant than urban, could not possibly hold the field as a written language against Latin and its successors, Navarrese Romance and, to a certain extent, Occitan (the langue d'Oc, also called Provençal) in the kingdom of Navarre. Since the 10th century, Basque has slowly but steadily lost ground to Castilian Spanish; in the north, however, where French is a more modern rival, the Basque-speaking area is practically the same as it was in the 16th century. In the last two centuries, above all in industrial centres, Basque has had to fight for survival in the heart of the Basque-speaking country, as well as on the frontier of the Basque-speaking area.

Latin inscriptions from the Roman period, found mostly in southwestern France, record a handful of proper names of unmistakable Basque etymology. From AD 1000 on, records consisting chiefly of proper names but also of Basque phrases and sentences grew more numerous and reliable. The first printed Basque book, dating from 1545, began an uninterrupted written tradition. Scholarly Basque literature, with its prevailing religious interests, has been neither abundant nor varied until recent times. Intense efforts are now being made to introduce Basque as a vehicle of private primary education. In addition, a model of a unified, standard written language also seems to be gaining increasing acceptance.