SUBIACO, a town of Italy, in the province of Rome, 25 miles east of Tivoli and 42 from the capital, is picturesquely situated on the right bank of the Teverone. It has iron-works and paper-mills, and in 1881 the population of the town was 6503 (commune, 7017), having decreased from 7452 in 1868.

Subiaco, the Sublaqueum of the Romans, was so called from its position under the artificial lakes constructed in connexion with one of the villas of the emperor Nero. In all probability there was no town in ancient times, and the modern town of Subiaco appears to have grown up subsequent to the establishment of the Benedictine monasteries in this neighbourhood. Of these the most remarkable are Santa Scolastica, which was built by the abbot Honoratus, and by the 11th century ranked as a regular principality; and Sacro Speco, which has gathered its curious cluster of buildings round the cave in which St Benedict himself found an asylum (see vol. iii. p. 557). The points of most interest in the town, which still bears on the whole a clearly mediaeval impress, are associated with Pope Pius VI. It was Pius who restored and extended the great castle, erected in 1068 by Abbot John V., and long used as a summer residence by the popes; and it was he who built the costly church of Sant’ Andrea. His visit to the town in 1789 is commemorated by a triumphal arch. The first book printed in Italy was the Subiaco Lactantius of 1465.