About 30 kilometers south of Rome, in the Alban Hills 500 meters above sea level, lies Lake Nemi. According to the Roman historian Suetonius, the emperor Caligula (37-41 CE built two ships at his imperial villa on the lake, and the memory of the sunken ships lingered in the tradition of the local fishermen. In 1446, the Renaissance Cardinal Don Pospero Colonna, Lord of Nemi, became the first man in modern times to attempt to raise the ships. Others followed until a systematic effort was begun by Eliseo Boghi in 1895. His efforts were so successful that the government intervened to stop his work and assumed direction of the search. It was finally decided to recover the ships by lowering the level of the lake, an effort undertaken between 1929 and 1932. In the words of Lieutenant Commander G. C. Speziale, the project "promised to be both difficult and costly, but very necessary from the point of general culture."
The two ships were found about 200 meters apart, lying at depths of 5 to 12 meters and 15 to 22 meters, respectively. The first galley measured 71.2 meters (239.5 feet) overall, 67.3 meters (220.7 feet) on the waterline and 20 meters in beam (65.6 feet), with a rounded bilge. The end of the stem curved back towards the stern of the ship, while the stern finial was in the shape of a fish tail. In general form, this vessel most closely conformed to what is known of Roman ships of the imperial period. The second galley was more rectangular in shape, measuring 73 meters overall (239.4 feet), 68.9 meters (226 feet) on the waterline, and 14.4 meters (47.2 feet) in beam. Ships of these dimensions were quite remarkable, exceeding by far the size of any known ships prior to the modern period. Tests on models of the two hulls demonstrated that they had low coefficients of friction for low-velocity ships intended to be sailed or rowed. Never intended for sailing on open water, they were lightly constructed, although the hulls were carvel built, with the planks joined edge to edge. To inhibit rot and fouling, the planking was covered by a layer of tar-impregnated wool clad in a thin sheathing of lead.
Among the artifacts found with or near the ships were interior decorations, including a bronze lion, leopard and fox heads originally fitted to the ends of bollards and beams, hinges, and fragments of porphyry, serpentine, mosaics, tesserae, and glass. Technological curiosities were an anchor with movable jaws of a type later developed by Lord Nelson in the eighteenth century, and two types of bearings: the larger, a type of bronze ball bearing, and the smaller, a needle bearing made of wood.
The discovery of so much material intended for ornament—coupled with Caligula's reputation as a libertine—led archaeologists to believe that the ships were intended simply as pleasure yachts. Other theories held that they were used for mock battles (though nothing of a martial character has been found at Nemi), that they were intended for secret naval experiments, and that they were somehow related to the temple of Diana Aricina. (The Romans called the lake Speculum Dianae.) A more recent theory holds that the ships were connected in some way with the mystery cult of Isis to which Caligula was an adherent. According to this explanation, the ships were intentionally sunk after the emperor's assassination as part of a policy to eradicate all memory of his rule.
Removed to shore facilities, the ships were the object of intense scholarly study during the 1930s, when several models of the vessels were made. During World War II, the ships were burned (probably intentionally) on the night of May 31, 1944, during the Allied advance on Rome. By 1996, a group called Dianae Lacus was developing plans to build full-scale replicas of the Nemi ships.
Denham, "Caligula's Galleys." Rubin de Cervin, "Mysteries and Nemesis of the Nemi Ships." Speziale, "The Roman Anchors Found at Nemi"; "Roman Galleys in the Lake of Nemi."
