CIVITAVECCHIA, a seaport town and episcopal see of Italy, province of Rome, 5om. N.W. by rail and 35m. direct from the city of Rome. Pop. (1921) 19,569 (town), 21,114 (corn mune) . It is the ancient Centum Cellae, founded by Trajan. In teresting descriptions of it are given by Pliny the Younger and Rutilius. The modern harbour works rest on the ancient founda tions, and near it was the cemetery of detachments of the fleets of Misenum and Ravenna. It was a strong populous place in the 6th century, but the Saracens destroyed it in 812. Leo IV. built a new city for the refugees 8m. N.N.E. of Civitavecchia, where may be seen ruins of walls and streets and an inscription, that must have stood over a gate, recording its foundation. The people returned to the old town (whence the name Civitavecchia) in 889, but the new one continued as the castle of Cencelle until the i 5th century. In 1508 Pope Julius II. began the construction of the castle from the designs of Bramante, Michelangelo being responsible for the addition of the central tower. Under it lies a Roman house, possibly the port admiral's quarters. Pius IV. added a convict prison. The arsenal was built by Alexander VII. and designed by Bernini. Civitavecchia was the chief port of the Papal State and has still a considerable trade. There are cement factories in the town, which will be considerably increased by the new electric railway to Orte, by which Terni (q.v.) is readily accessible. In 1926 ships to the number of 2,285, a total tonnage of 2,041,637, entered and cleared the port, and 789,921 tons of merchandise were imported (chiefly coal and cereals) and exported (chiefly salt) from the saltworks of Porto Clementino, south-west of Tarquinia. There is a thermal establishment in the town, and 3m. N.E. were the Aquae Tauri, warm springs; considerable re mains of the Roman baths of the time of Trajan are still pre served there. About one mile west of these are hot springs (the Ficoncella), also known in Roman times. Five miles down the coast is the summer resort of S. Marinella, which has grown up in the last 20 years and forms a part of the commune of Civitavecchia.