Mount CirceoCirceius Mons (mod. Monte Circeo), an isolated promontory on the southwest coast of Italy, about 80 miles south/southeast of Rome, in the littoral between Anzio and Terracina. It is a ridge of limestone about 3 miles long by 1 mile wide at the base, running from east to west and surrounded by the sea on all sides except the north. The land to the north of it is 53 feet above sea level, while the summit of the promontory is 1775 ft. The origin of the name is uncertain: it has naturally been connected with the legend of Circe, and Victor Bérard (in Les Phéniciens et l'Odyssée, ii. 261 seq.) maintains in support of the identification that Aiai~, the Greek name for the island of Circe, is a faithful transliteration of a Semitic name, meaning "island of the hawk," of which cijiros KLpic~~ is the translation. The difficulty has been raised, especially by geologists, that the promontory ceased to be an island at a period considerably before the time of Homer; but Procopius very truly remarked that the promontory has all the appearance of an island until one is actually upon it (see  ).
Upon the east end of the ridge of the promontory are the remains of an enceinte, forming roughly a rectangle of about 200 by 100 yards of very fine polygonal work, on the outside, the blocks being very carefully cut and jointed and right angles being intentionally avoided. The wall stands almost entirely free, as at Arpinum—polygonal walls in Italy are as a rule embanking walls—and increases considerably in thickness as it descends. The blocks of the inner face are much less carefully worked both here and at Arpinum. It seems to have been an acropolis, and contains no traces of buildings, except for a subterranean cistern, circular, with a beehive roof of converging blocks. The modern village of San Felice Circeo seems to occupy the site of the ancient town, the citadel of which stood on the mountain top, for its medieval walls rest upon ancient walls of Cyclopean work of less careful construction than those of the citadel, and enclosing an area of 200 by 150 yards.
Circeo was founded as a Roman colony at an early date— according to some authorities in the time of Tarquinius Superbus, but more probably about 390 BC. The existence of a previous population, however, is very likely indicated by the revolt of Circei in the middle of the 4th century B.C., so that it is doubtful whether the walls described are to be attributed to the Romans or the earlier Volscian inhabitants. At the end of the republic, however, or at latest at the beginning of the imperial period, the city of Circei was no longer at the east end of the promontory, but on the east shores of the Lago di Paola (a lagoon—now a considerable fishery—separated from the sea by a line of sandhills and connected with it by a channel of Roman date: Strabo speaks of it as a small harbour) one mile north of the west end of the promontory. Here are the remains of a Roman town, belonging to the 1st and 2nd centuries, extending over an area of some 600 by 500 yards, and consisting of fine buildings along the lagoons, including a large open piscina or basin, surrounded by a double portico, while farther inland are several very large and well-preserved water-reservoirs, supplied by an aqueduct of which traces may still be seen. An inscription speaks of an amphitheatre, of which no remains are visible. The transference of the city did not, however, mean the abandonment of the east end of the promontory, on which stand the remains of several very large villas. An inscription, indeed, cut in the rock near San Felice, speaks of this part of the promonturium Veneris (the only case of the use of this name) as belonging to the city of Circei. On the south and north sides of the promontory there are comparatively few buildings, while, at the west end there is a sheer precipice to the sea.
The town only acquired municipal rights after the Social War, and was a place of little importance, except as a seaside resort. For its villas Cicero compares it with Antium, and probably both Tiberius and Domitian possessed residences there. Presumed Domitian's villa contained important artistic works, like the Apollo and the Faun with the transverse flute and a spa. The beetroot and oysters of Circei had a certain reputation. The view from the highest summit of the promontory (which is occupied by ruins of a platform attributed with great probability to a temple of Venus or Circe) is of remarkable beauty; the whole mountain is covered with fragrant shrubs. From any point in the Pomptine Marshes or on the coast-line of Latium the Circeian promontory dominates the landscape in the most remarkable way.
See T. Ashby, "Monte Circeo", in Melanges de l'école française de Rome, xxv. (1905) 157 seq. (T. As.)
from a 1911 encyclopedia
Apart from Circe's legend and roman remains, this area has other historical contents: in 1939 a skull of a Neanderthal man was found (prof. Blanc, Guattari's cave), and several other findings proof it was inhabited in prehistorical times.
Mount Circeo is today a natural protected park (see  ) instituted in 1934 on 8,500 hectares over the territories of Latina, Sabaudia, San Felice Circeo and Zannone Island (minor island of Ponza).