The Pontine Marshes ( , ; , formerly also ; [] by Titus Livius,History of Rome, 6.5.2. [] and [] by Pliny the ElderNatural History 3.59.Natural History 26.9.) is an approximately quadrangular area of former marshland in the Lazio Region of central Italy, extending along the coast southeast of Rome about from just east of Anzio to Terracina (ancient Tarracina), varying in distance inland between the Tyrrhenian Sea and the Volscian Mountains (the Monti Lepini in the north, the Monti Ausoni in the center, and the Monti Aurunci in the south) from The northwestern border runs approximately from the mouth of the river Astura along the river and from its upper reaches to Cori in the Monti Lepini.
The former marsh is a low tract of mainly agricultural reclaimed land created by draining and filling, separated from the sea by sand dunes. The area amounts to about .. The Via Appia, a Roman military road constructed in 312 BC, crosses the inland side of the former marsh in a long, straight stretch flanked by trees. Before then, travelers had to use the Via Latina along the flanks of the mountains; Terracina could not be reached across the marsh.
Further southward along the coast as far as Minturno is another stretch of former coastal marsh called the South Pontino, the largest section being between Terracina and Sperlonga, as far inland as Fondi. It was part of ancient Latium adiectum and still belongs to Lazio. Bordered by the Aurunci Mountains, this land is mainly reclaimed, as well, but the more frequent incursion of hills permitted more dense settlements. Leaving Terracina, the Via Appia crosses it, as well.
The marsh was an extensive alluvial plain at about sea level (some above, some below) created by the failure of the streams draining the mountains to find clearly defined outlets to the sea through the barrier dunes.. Above sea level, it was a forested swamp; below, it was mud flats and pools. Sparsely inhabited throughout much of their history, the Pontine Marshes were the subject of extensive land reclamation work performed periodically. The tribe of the Volsci began with minor draining projects in the vicinity of Tarracina in connection with their occupation of it in the pre-Roman period.
The road proved difficult to keep above water. Under Augustus, a compromise was reached with the construction of a parallel canal. The part of the marsh above sea level was successfully drained by channels, and new agricultural land of legendary fertility came into being. Whenever the channels were not maintained, the swamp reappeared. Meanwhile, frequent epidemics of malaria at Rome and elsewhere kept the reclamation issue alive. Under Benito Mussolini's regime in the 1930s, the problem was nearly solved by placing dikes and pumping out that portion of the marsh below sea level. It continues to need constant maintenance. Italian confidence in the project was so high, the city placed by Mussolini in 1932 in the center of the marsh, Latina, formerly named Littoria, became the capital of a new province, Latina.
Geology The Agro Pontino geologically is one of four geomorphic divisions of a somewhat larger area, the Pontine Region, also comprising the Monti Albani, the Volscian Mountains and Monte Circeo; in short, all of Roman Latium.Van Joolen Chapter 1 2003 p. 10. The marsh itself was located in Latium Novum, the eastern part of the region, which the Romans removed from the sovereignty of the Volsci. The two terms create some confusion in the literature, as the region was often heavily settled, but the marsh supported no resident population.
Pliocene The underlying landform is a horst–graben, in which expansion of the crust causes a section to drop, creating a rift valley. Underneath the marsh is such a valley, while the steeply-sided Volscian Mountains and the floor under the outer dunes are the corresponding horsts. The graben was formed over a period approximated by the end of the Pliocene about 2.588 million years ago. The natural outcome of this graben topography was the creation of outer barrier islands and a lagoon that gradually filled with runoff sediment transported from the mountains.
Pleistocene The rift valley remained a depression in the Tyrrhenian Sea for about two million years and then in the Tuscolano-Artemisio phase, dated 600–360 thousand years BP, a series of volcanic changes began leading to the current landform: the first four eruptive cycles of a new volcano in the vicinity of the Monti Albani, which spread pyroclastic rock and formed a caldera. In the Campi di Annibale phase, 300–200 thousand years BP, a stratovolcano formed in the caldera. Approximately contemporaneously, in the Middle Pleistocene, 781–126 thousand years BP, beds of sand and clay, termed the Latina Complex, appeared above sea level over the outer karst, enclosing a lagoon.Van Joolen Chapter 1 2003 p. 11. The beaches survive at the Latina Level from about 560 thousand years BP.
The Tyrrhenian II transgression of ocean water into the lagoon left the Minturno level and complex, a dune barrier of about , dated 125–100 thousand years BP.Van Joolen Chapter 3 2003 p. 65. Behind the beach, deep peat and clay deposits alternating with alluvial sediments evidence the lagoon. It was deepest at the Terracina end diminishing to the surface at Cisterna, where beds of travertine, sand fused by volcanic activity, reach the surface. At this time, Latium Vetus had been formed as a volcanic land mass, while Latium Novum was a lagoon, the future marsh.
The Tyrrhenian III transgression left the Borgo Ermada Complex and Level, about 90 thousand years BP. It consisted of elongated sand ridges parallel to the shore, high. During the regression phase, fluvial incisions indicate by then at very latest, the lagoon was totally enclosed. After it drained, aeolian (wind-driven) sand covered the notches.
At around 22 thousand years BP, the volcanic complex became active for the last time, erupting in hydromagmatic explosions that created the beds of Lakes Albano and Nemi, both crater lakes.
Holocene The most recent beach, the Terracina Complex and Level, which began the Holocene about 11700 years BP, was a single ridge behind which clay, peat, and peaty clay were being deposited at sea level. No land was yet above it. The region was a shallow lagoon interspersed with marshland. Fluvial incisions in the beach let out the excess water, which was brackish and contained salt-water mollusks, leading to the question of where the excess water came from and why alluvial fans had not buried the region. The answer is in the composition of the Volscian Mountains, which are limestone, porous, and excessively cracked and faulted. All but the heaviest rainfalls sink into the rock only to appear as a large volume of spring and groundwater at the foot of the mountains. Transport of sediment was minimal. In one estimate, flow from springs over a distance of . In another estimate, 80% of the rain falling on the Monti Lepini is absorbed, with a single spring at Ninfa exuding . These facts explain why the main fill of the lagoon is peat, silt, and clay, and not thicker-grained alluvial deposits, and why it took so long.
Alluvial deposits known as the Sezze Fan began about 4000 BC in the marsh below Sezze. The increased rainfall required to move the sediment is attributed to the Atlantic Period, a time of warmer and moister climate dated around 5000–3000 BC. Pollen from the marsh indicates the replacement of mixed oak by alder and willow.Van Joolen 2003 Chapter 3 p. 79. The modern rivers incised the marsh: the Ufente, the Sisto, and the Amaseno, which had shifting rather than stable tributaries. The marsh drains to the southeast, with channels parallel to the coast, exiting between Circeo and Terracina. Although settlement on the mountain slopes began much earlier, deforestation by the Volsci began in the sixth century BC. The marsh rapidly acquired the alluvial deposits of the Amaseno Fan over the peat, bringing much of it above water. No buried soils indicate any cultivation of dry land in the marsh.
Archaeology Archaeological work on the marsh has been extensive, including surveys, excavations, and core samples. Four land systems have been defined: Fogliano coastal, the beach system; Borgo Grappa Beach Ridge, the region just inland from the beach, rather extensive in the Circeo section; the Latina Plain, the main part of the fields; and the Monti Lepini, the flank of the mountains.Van Joolen 2003 Chapter 3 p. 64. The center of the marsh, earlier the lagoon, although currently urban, does not provide any ancient evidence of habitation. The land (or the lake) was undoubtedly uninhabited except possibly for itinerant fowlers and fishers, but further, any evidence of human activity there would be deep in the underlying peat. In the fringes, however, most anciently at the north edge of the lagoon and in the coastal fringe, in both the Fogliano and Borgo Grappa land systems, evidence of hunting-gathering dates from the Middle Pleistocene. Evidently, man has witnessed the entire history of the lagoon and marsh from its first formation, when he hunted and fished along its shores.
Paleolithic Paleolithic material comes from Campoverde at the north edge of the Pontino Agro. It is dated by typology, as none has been found in context. The assemblage of amateur collections of surface artifacts "shares affinities with various Lower Palaeolithic industries of Latium. Chronologically referred to the second half of the Middle Pleistocene;". that is, about 500 thousand years BP. These are primarily flint cores and flakes, consisting of denticulate tools, side scrapers, borers, retouched flakes, some microliths, and others. Also from Campoverde come animal bones excavated unscientifically from a trench during construction and one human tooth. The latter is too large to be of modern humans and has been assigned the genus Homo. The animals include Elephas antiquus, Mammuthus primigenius, Equus ferus, Bos primigenius, Cervus elaphus, Capreolus capreolus, and others.
A skull of Neanderthal man was found in a grotto on Monte Circeo in Italy on February 25, 1939, by a team of paleontologists headed by Alberto Carlo Blanc dating to about 65 thousand years BP. On May 8, 2021, 9 Neanderthal skeletons were discovered in the same cave by a team of archaeologists. The team concluded that the Neanderthals were killed by a pack of hyenas.
History
Roman times The geographers and historians of the early Roman Empire describe the marsh.
Livy reported that after the Secessio plebis of 494 BC, a strike by the common people for political rights, a famine occurred at Rome due to decreased economic activity. Grain buyers were sent to "the people of the Pomptine marshes" and elsewhere to acquire new supplies, but were met with refusal. The Volsci attempted to exploit this momentary weakness by raising an army of invasion but were struck down by an epidemic, of what sort, or whether historians can conclude to be malaria, remains unsaid. The Romans, buying grain in Sicily, reinforced their colony at Velitrae and planted a colony at Norba, "which thus became a fortified point for the defense of the Pomptine region."History of Rome, 2.34. In 433 BC, Rome was struck by an epidemic and again sent buyers to the Pontine, this time successfully.History of Rome, 4.25. Apparently, at least some of the marsh was under cultivation, which the high density of Roman settlements along the two northern roads might lead one to expect.
Strabo says:Geography, 5.3.6."In front of Tarracina lies a great marsh, formed by two rivers; the larger one is called the Aufidus (Ufente). It is here that the Appian Way first touches the sea ... Near Tarracina, as you go toward Rome, there is a canal that runs alongside the Appian Way, and is fed at numerous places by waters from the marshes and the rivers ... The boat is towed by a mule."