 The Asturians devastated several towns and villages on the banks of the Douro River, and carried off local populations from the towns and villages in the Galician-Leonese lowlands back to the mountains, creating an empty buffer zone in the Douro River valley (the "Desert of the Duero") between the Asturias in the north and al-Andalus in the south.This newly emptied frontier would remain in place for the next few centuries.It is alleged that pastoral Berber mountaineers remained behind in the highlands around Astorga and León.