ASTURIAS, a principality of Spain, created (1388) by John I. of Leon and Castile when his eldest son Henry married the daughter of the duke of Lancaster. The principality, now purely titular, belongs to the eldest son of the sovereign; administratively the principality is chiefly merged in the province of Oviedo, to describe which Asturias still survives popular usage as a regional term. Clearly defined on three sides by mountain ranges which make the district a rough oval, and on the fourth side by a long straight coast-line, broken only by the projecting Cabo de Penas, the Asturias are secluded from the rest of the peninsula and such outlook as they have is maritime. On the east the triple limestone massif of the Picos de Europa, reaching 2,600m., leaves only a narrow strip for passage to the coast of old Castile ; on the south the Cantabrian mountains shut off the central plateau to which no pass lower than 1,13om. gives access, the main road from Oviedo to Leon crossing by the Puerto de Pajares at 1,363m.; on the west the lower Sierras de Ranadoiro and de Meira, running north-east to south-west, block the road to Galicia; between these sierras the boundary-line of the Asturias runs without any special natural definition to the Ria de Rivadeo.
The abrupt descent from the Cantabrian crest, which reaches 2,3oom. in Pena Ubina, brings down the rivers by steep courses set in deep valleys—in canyons, in the mountain limestone of the eastern Asturias—to the sea, nowhere more than 7okm. distant. A fan-shaped area drains to the Ria de Pravia by the converging rivers Narcea and Nalon; the town of Pravia stands at the apex of the fan. Besides these rivers and their tributaries, the Navia and Sella are the only important streams. To the east of this fan, behind the coast between Aviles and Caravia, lies the area of successive marine invasions in geological times. To one of these invasions is due the natural trench which forms the central valley of the Asturias east of Oviedo, and which continues along the line of the old sea-gulf narrowing out between the Picos de Europa and the Sierra de Cuera. This structural valley, neither the result of stream action nor occupied by any important stream, gives the principal interior line of communications in the Asturias. Along the coast the great Cantabrian platform, running from western Galicia to the mouth of the river Adour in France, is represented in the Asturias as elsewhere, by the gently rolling "downs," some 6o or Tom. in height and cut usually in sheer cliffs towards the sea, into which the platform, segmented by the rivers from the interior, has been moulded by the weather. To-day the platform is thickly populated, and one single coastal road connects the long line of small towns set on successive heights. The intervening rigs are clogged with silt and afford no good harbours. The relief, of mountain, valley and coastal plat form, the coal supply and the humidity of the climate determine jointly the character of the Asturias. The impenetrable Picos de Europa, in whose fastnesses the chamois still roams, sheltered the Christian nucleus of resistance to the Muslims, which de veloped into the kingdom of Oviedo and Asturias. In the early stages of this resistance the term Asturias (derived from the original inhabitants, the Astures, whose territory extended west wards from Ribudesella and as far as the Douro) covered loosely the Cantabrian territory held by the Christians; there were Asturias in the Liebana valley and as far east as Santander (Asturia de Sancto Anderio), and the name lingered long east of the Picos in the term Asturia de Santillana (Sancta Illana). But the important movement was westwards along the central valley, in which Cangas de Onis and Oviedo (alternating with Pravia) were successive headquarters or capitals of the small Christian State. After the capital of the enlarged State had been transferred to Leon by Ordono II. (914-924), the isolation of the Asturias and of Galicia, both from each other and from the repopulated territory on the central plateau, contributed to the weakness and lack of homogeneity of the kingdom of Leon. The mountain barrier between Leon and the Asturias made Oviedo at a later date a refuge for the Leonese king Bermudo II. during the raid of Almanzor.
The coal of the Asturias lies in distinct groups of small basins; the town of Tineo is the centre for the most westerly group, but the comparatively thick beds of anthracite coal have been little exploited there for lack of means of communication. The most important group at present is the central; here the coal lies in a series of folds of the mountain limestone, cut by the rivers Caudal and Nalon, on which Mieres and Langres are respectively the centres of exploitation. The more northerly basins of Arnas and Ferrones supply a soft coal with 45% of volatile substances, and, speaking generally, the coals of the Asturian basins form a descending scale of hardness from north to south. Iron ore is also extracted in the Asturias and blast furnaces have been erected at La Felguera to treat it. Zinc ores are mined in the Picos de Europa. The altitude at which the zinc is found, however, pre vents operations in winter ; the iron ores have a high percentage of silica ; the coal seams are relatively thin and irregular and they dip steeply, so that the costs both of production and of trans port are high. Thus the mineral resources of the Asturias have served to industrialize considerable tracts of country without bringing any high degree of prosperity. The temporary prosperity of the abnormal war years and the new capital sunk in conse quence of this prosperity in improved machinery (calculated as equivalent to some eight millions of pounds sterling for the decen nium 1915-25) have had the effect of raising in a more acute form in recent times the question of the protection by governmental decree of Asturian coal. With a humid climate and a high rainfall, nowhere less than i,000mm. per annum, the Asturias are predom inantly pastoral and the cow is the chief domestic animal. Horses and mules are bred on the Asturian pastures but they are not worked, except in the mines. The absence of a regular period of drought, together with favourable temperature conditions, makes maize the chief cereal cultivated ; the soils do not, however. favour the cultivator and America and the mines attract labour more than the farm. The marked summer minimum of rainfall is sufficient to make ordinary summer irrigation desirable, but the typical Asturian irrigation is the winter flooding of lands by running water, partly to maintain the soil temperature and partly to secure the benefit of the fertilizing deposit of mud.