CASTILE, an ancient kingdom of Spain, bounded on the north by the Bay of Biscay, north-east by the Basque provinces and Navarre, east by Aragon, south-east by Valencia and Murcia, south by Andalusia, west by Estremadura and Leon, and north west by Asturias. Pop. (1926) estimated 4,494,872. Area, sq.m. The name is said to be derived from the numerous fron tier -forts (castillos), erected as a defence against the Moors. The territorial extent of mediaeval Castile grew with progressive conquests from the Moors. From a mere county in the north (Old Castile) the kingdom extended to include the whole of central Spain. The final successful resistance of Asturias was followed by the liberation of Galicia and Leon and in the time of Ferdinand I. of Castile (1035-1065) the kingdoms of Leon and Castile were united. New territories were annexed on the south and the capture of Toledo in 1085 saw the formation of New Castile.
The centre of Old Castile is the basin of the Upper Douro, that of New Castile the trench-like upper basins of the Tagus and Guadiana. In 1833 Old Castile was divided into the provinces of Avila, Burgos, Logrono, Palencia, Santander, Segovia, Soria and Valladolid; while New Castile was similarly divided into Ciudad Real, Cuenca, Guadalajara, Madrid and Toledo (qq.v.). The entire area extends for about 30o m. from north to south, and 160 m. from east to west. It is a plateau, with average altitude about 2,500f t. and a natural frontier of high mountains on all sides, except on the borders of Leon, Estremadura and Murcia. On the north-west are the Sierra de Culebra and the high plains of Leon, on the north the Cantabrian mountains, on the east the Sierra del Demanda and its offshoots. The Sierra de Gaudarrama, Sierra de Gredos and Sierra de Gata extend across the centre in a south-westerly direction, forming the southern boundary of Old Castile. The Sierra de Albarracin and Sierra de Cuenca continue the mountain girdle of New Castile on the east, with parts of the Sierra Morena forming its southern boundary. The mountains on the south-west are less definite and include the minor ranges that more or less unite the Sierra de Gredos, Sierra de Guadelupe and Sierra Morena. This highland region, shut off from the sea, is exposed to extremities of heat and cold. Snow falls early and lies late on the mountains of the north and there is a heavy rainfall in the north-west. The southern regions of New Castile are more arid with a rainfall rarely exceeding I o inches in the year. The country is swept by bitter gales in win ter and scorching dust-laden winds in summer. In both the Cas tiles the plateau-soil is naturally fertile, and after rain a luxuriant vegetation appears; but drought is common. In the neighbour hood of Valladolid, Palencia and in the Mesa de Ocana, where heavy loam underlies the porous surface, moisture which else where is absorbed remains available. On the mountains sur rounding the plateau vast tracts are useless except as pasture for sheep, and the severe winters drive the sheep to migrate yearly into Estremadura (q.v.). On the wheat-growing lands arose cen trally situated cities, like Valladolid, Palencia and Toledo, while arranged around them at the foot of the mountain passes grew up a ring of smaller centres, mediaeval market towns where the produce of the plains was exchanged for that of the highlands. In Old Castile we have Leon, Burgos, Segovia, Avila and Sala manca; in New Castile, Guadalajara, Cuenca, Albacete and Ciu dad Real. Salamanca, linked with the Moorish south, became the historic university of Christian Spain, while Toledo was a link between north and south—Christian and Moor. At Alcala de Henares was established in 1510 another university.
Castilian is the literary language of Spain, and with certain differences, of Spanish America also. It is spoken in Old and New Castile, Aragon, Estremadura and the greater part of Leon; in Andalusia it is subject to modifications of accent and pro nunciation. Cut off on all sides from the sea and full of mem ories of the bitter struggle with the Moors, this region has pre served many mediaeval features in its life. Madrid (q.v.) grew up following the defeat of the Moors, and has little relation to the evolution of Castile.