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 entry Aug 2009              

he Roman Port of Pozzuoli

                                                                                                                                                                The arched pier of Roman Puteoli (Pozzuoli)

Changes in the coastline of the Gulf of Naples —specifically the Bay of Pozzuoli— have come about over the centuries not so much through general changes of sea-level in the Mediterranean, but rather through the local rising and falling of the land from earthquakes and especially the minor (but cumulatively important) up-and-down jiggling shifts known as "bradisisms." The area is on top of —better, IS the top of— an active seismic cauldron that has to vent every once in a while.

Though there is considerable discussion over the extent to which the coastline has changed since the time of the Romans, it is a matter of simple (albeit underwater!) observation that there are submerged Roman buildings and port facilities in the bay off of Pozzuoli and adjacent (to the west) Baia. The movement, by the way, has not always been all in one direction; that is, since the 1980 earthquake and subsequent bradisisms, the land has actually risen, not subsided; the famous Temple of Serapis (photo, left)—which used to be submerged up to about the one-meter mark on the columns—is now totally on dry land, and the entire port had to be rebuilt in the 1980s to accommodate the drop in perceived sea-level at portside.

Also see these entries:

 Imperial Port of Baia    the Baia Castle and Museum    the geology of Pozzuoli

The modern sea-wall that shelters the port disguises history rather well. When the Roman empire fell, Pozzuoli, with the adjacent imperial glory of the port facilities of Baia, went into centuries of decline. As late as the 1880s, a travel writer in the New York Times could still say:
...The harbor of Pozzuoli is an interesting place to visit, if only to study the manner in which the ancients built their piers. There still remains the tremendous structure, or a very large portion of it, called by Seneca, Pilae, and by Suetonius, Moles Puteolanae. Of 25 buttresses, which supported 24 arches, 16 are left, three being under water. They are constructed of brick and pozzulana earth, and bear an inscription reporting that the pier was restored by Antonius Pius. A common, but very erroneous impression, owing probably to the fact of the pier now being called Ponte [bridge] di Caligula, is that it was connected with the ponton [sic] bridge which that emperor threw across the bay of Baiae in order that, clad in the armor of Alexander the Great, he might there celebrate his insane triumph over the Parthians
(For more on Caligula and his bridge, see A Roman Bridge to Baia.)

Indeed, photos from that period (below, right) show the pier/sea-wall of Pozzuoli to be low and jagged, essentially what is left of the old Roman structure (seen in the above image) after many centuries of neglect. (Sources differ as to how many arches the original Roman pier had.) After a century of talk about rebuilding the pier into a more modern structure, it wasn't until the early 1900s that this was done. Dvorak (sources, below) reports in 1904:

Pozzuoli. Photo, Roberto Rive, c. 1880                 

The largest and best-known Roman breakwater is that at Puteoli, commonly called the Bridge of Caligula. This great work consisted of fifteen tall piers of concrete, some of 52 feet square, others smaller, rising from 49 feet of water to some 16 feet above the surface. The tops of the piers were connected by arches, and the whole work was often referred to as the "opus pilarum," or "moles puteolanae." Unfortunately, but little of the old work is now to be seen, for the  harbour is sheltered by a solid sea-wall, which has been constructed by filling up the spaces between the ancient piers. The work was originally proposed by Carlo Fontana, and, in spite of the adverse criticism of Fazio, will soon be finished.

    The modernizing work was, indeed, finished and was, as noted, redone in the 1980s. Roman engineers built differently than modern ones. A modern seawall stops waves completely; the Romans, however, built separate piers (in this case, joined by arches) that were close enough to break the main force of the waves but still let sufficient water pass through. Without modern dredging equipment, this had the advantage of letting currents sweep through the harbor and keep the port from silting up. Perhaps the most interesting thing in the whole harbor was the small island off the end of the pier (seen in the image at the top of this page). It was covered with buildings and has disappeared completely; it is probably the one mentioned by the Greek historian Pausanias in the second century AD:

Off Diceearchia [the original Greek name for Pozzuoli, ed.], which belongs to the Etruscans, there is boiling water in the sea, and an island has been constructed artificially, that the water may be utilized for warm baths.

The modern sea-wall of Pozzuoli (jutting out on the right in this photo) runs almost exactly east to west, pointing directly at Baia.

    Much of the western part of the bay, off of Baia, has been studied and made available in the new museum in the Aragonese castle off of Baia; those waters are also now an "underwater archaeology park," but I don't know the extent to which such efforts have extended to Pausania's "artificial island." Also, there was apparently a second harbor at Puteoli. Ancient sources mention it and in the early 19th century, engineers planning to rebuild the harbor spoke of the existence of an extensive network of piers offshore below the old acropolis to the east of the main harbor.


*1: The arched pier is reproduced in Dvorak (below) and labelled "from a Roman picture after Bellori" in reference to Fragmenta vestigii veteris Romae by J.P. Bellori (1615-1696), a French archaeologist. (back to text)


—Dvorak, John J. and G. Mastrolorenzo (1991). The Mechanisms of recent vertical crustal movements in Campi Flegrei, Southern Italy. The Geological Society of America, Special Paper 263. Boulder, Colorado.
—Fazio, G. (1832).
Discorso intorno al sistema di costruzione de Porti. Naples.
— Günther, R. T. (1903) "Earth-Movements in the Bay of Naples. IV. The Phlegræan Shore-Line." in The Geographical Journal, Vol. 22, No. 3 (Sep., 1903), pp. 269-286. Blackwell, London.
—"Pozzuoli and her renown" in The New York Times, July 9, 1881.
—Sirago, Maria (2008). La trasformazione dei porti e degli arsenali del regno di Napoli nel passaggio dalla propulsione remica a quella velica [The transformation of ports and shipbuilding in the kingdom of Naples in the transisition from oars to sails] in the annals of the 2. National Meeting on the History of Engineering, Naples, 7-9 April 2008, pp. 1017 – 1027.

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