The name Valcarlos. It recalls the Basque epic poem but is a name imposed by romancers. Its Basque name is Luzaide. The foreign name already appears in the 12th century in the 13th century Archbishop Rodrigo Ximenez de Rada: Carolus... procedens per vallem quae Vallis Caroli dicitur, et planior invenitur, ne ascendants impedidet asperitas Pyrenaei... Carlos... advancing through the valley called Valle de Carlos, and is flatter, so that the roughness of the Pyrenees would not impede their climb... The name Rozavalles in the Nota Emilianense (11th century) refers to the Burguete plain located in front of Roncesvalles with the meaning of plain of Erro, which is the valley to which it belongs. Then it would no longer be called Rozavalles but Errozabala, without making reference to a valley of any kind. Otherwise, the etymology would be Latin.