La gran aventura de la lengua española

Accounts describe its origins as a dialect derived from the Latin spoken in the Castilian highlands and its subsequent expansion driven by the military campaigns of the Reconquista. It all began in a small district in the north of the Iberian Peninsula—a narrow corridor bounded to the north by the Cantabrian Mountains, to the west by the Pisuerga River, to the east by the Basque Mountains, and to the south by a vast, sparsely populated expanse that historians would later call the Duero "desert." It was a frontier land of near-constant conflict where dozens of peoples had clashed over the ages. Romans—who imposed their language, Latin—passed through, followed by the Visigoths and, later, the Arabs. The Reconquista began in the 8th century. The lands of the plateau became dotted with fortifications and sturdy stone castles; there were so many of them that they gave the region its name: Castile.