An ancient and interesting town of Central Italy; occupies a pleasant site amid encircling hills on the Teverone, 32 m. E. by N. of Rome; has a quaint, mediaeval appearance, and is overlooked by an old castle, a former residence of the Popes; there are two Benedictine monasteries dating from the 6th century, and in a grotto near St. Benedictine lived, in his youth, a hermit life for three years.