Ayila. I. A province of Spain, forming the S. W. part of Old Castile, and bordering on New Castile and Estremadura; area, 2,981 sq. m.; pop. in 1867, 176,769. The northern portion of the province is generally level, of moderate fertility, and the inhabitants are engaged in agriculture. The southern part is intersected by numerous rocky mountain ranges, with verdant valleys between. Here the raising of cattle is the most important branch of industry. The Alberche and the Adaja, respectively affluents of the Tagus and the Douro, are the principal rivers. Two centuries ago the province was wealthy and populous, but it has gradually decayed, in consequence of the burdensome manorial and feudal privileges, and the laws of entail and mortmain. Merino wool is the chief article of production. Besides the capital, it contains no town of importance. II. The capital of the preceding province,' an episcopal city, situated on the Adaja, 53 m. W. N. W. of Madrid; pop. about 7,000. It had formerly a flourishing university and extensive woollen manufactures, but its ancient prosperity has departed. The city is encompassed by a wall, still in good repair, with towers of great strength. It has a line old cathedral and a Dominican convent, both of which contain some beautiful monuments.

The church of San Vicente, without the walls, said to have been erected in 313, is an interesting object.