Originally it was known as "Gothic Plains" ("Campi Gothici" or "Campi Gothorum"), as the area had been settled by Visigoths who fled from Aquitaine Gaul after its conquest by the Franks. It was first mentioned under this name in "Codex Vigilanus" "(Codex Albeldensis)", and described as extending ""from the river Douro, to the Christian Kingdom"".