ETRUSCAN: ITALY’S FIRST CIVILIZATION.

                                                                                                                                                                                                                                                       

The Etruscans are a now extinct and long ignored Iron Age culture which flourished in northwestern Italy from about the 8^th. century BC to the 3^rd century BC. They were Italy’s first great civilization. The Etruscans were sophisticated, literate, wealthy,  and militarily powerful, miners, metallurgists. seafarers and traders. Earliest evidences of Etruscans in Italy occur around 900BC and continue to about  27BC when the last communities were absorbed by Rome.  The Etruscan’s early and advanced culture was systematically “cleansed” out of existence by their neigbors to the south—the Latins. Little was known about Etruscans until archaeological excavations  revealed their tombs, artifacts, sculpture, alphabet and writings in relatively modern times.  

Long before the Romans, this Iron Age (1200BC to 550BC) culture achieved excellence in copper mining, and smelting and bronze metal work.  Their skill with bronze (an alloy of copper and tin or arsenic) is legendary. See: https://www.alamy.com/stock-photo/etruscan-bronze-statue.html?sortBy=relevant

They built magnificent tombs for their afterlife, often filled with objects of great beauty and value. 

https://www.romecabs.com/blog/docs/10-amazing-etruscan-tombs-banditaccia-necropolis-in-cerveteri/

Much of their statuary, and artwork was rendered in terracotta of which they were also masters. https://www.metmuseum.org/art/collection/search/249091

They were the first to produce vases and jugs of ceramics which were made to resemble other more valuable material substances…most famously their pottery, known as:“ Bucchero ware”  which was produced to closely resemble  bronze metal.  http://www-01.glendale.edu/ceramics/buccheropitcher.html. They were also master jewelry makers, specializing in gold granulation and applied filigree https://blog.dma.org/2012/02/14/how-its-made-etruscan-jewelry/amp/

Roman religion, Roman architecture ( the barrel arch and vault), engineering, road building, and even the the traditional dress :the Roman toga, were all taken by the Romans from Etruscans. The Romans studiously ignored the origins of these many contributions and even developed myths to supersede and hide the source as from the talented Etruscans.   See https://www.thecollector.com/etruscan-influence-rome/

They were hydrologic engineers too, designing and supervising the building the famous Cloaca Maxima-the world’s first sewer system, which first drained the marshes between the Seven Hills, and served to carry Rome’s human wastes into the Tiber River. https://www.thecollector.com/who-were-the-etruscans/

Most archaeologists support the idea that Etruscans were a native Italian culture, most likely arising from a earlier or proto-Villanovan  Bronze Age (@3000 BC-1200BC) culture which is known to have occupied parts of Etruria, cremated their dead and  buried their ashes in cone shaped urns of impasto pottery (terracotta)-uniquely topped with another cone. The combination is claimed to have simulated the circular thatch roofed houses constructed by this culture.  The burial cones were often decorated with geometric designs. Elite burials often containing bronze weapons or bronze horse-harness fittings, bronze fibulae (large “saftey pins” used to close the toga), candelabra, and jewelry. The offerings suggest a high level of technical advancement. The urns with offerings  were separated from other burials with no grave offerings. These assumed “elite” burials are often assumed to indicated that the culture had a hierarchy of elites. 

     

One objection to this idea of origin from local cultures is that the Etruscan homes were not circular, post raised, homes with conical thatch roofs, but rectangular structures with terracotta roofs.  See “tombs” above. 

For many historians the sophistication of the Etruscans,  their unique non-Indo-European language, all suggested that they were “transplants” from foreign lands. The Greek historian Herodotus ( 484BC -425BC) a contemporary of Etruscan society, writes that the Etruscans were immigrants from “Lydia”, a Greek outpost on the western coast of modern-day Turkey (Anatolia) .  Herodotus was born in Anatolia, lived in Athens and Italy, and he or his informants were likely to have had intimate knowledge of living Etruscans.  In support of Herodotus, modern linguists support the idea that the Etruscan spoke a language very different from all those in Italy and on the basis of linguistics it is likely that they were immigrats from afar. Etruscan has no relationship to other Indo-European languages of Italy. But they were most likely not from Lydia as Herodotus claimed. Etruscan customs are very different form that of the Lydians and Lydians spoke an Indo-European language unrelated to that of the Etruscans.  

However the Etruscan language does appear to be related to a language known as Rhaetian which was spoken in the Eastern Alps in pre-Roman times.  

Several recent DNA studies from Etruscan burials have concluded that the Etruscans  were simply talented “locals”. But some have questioned these evidences on the basis of the fact that genetic data from long buried human bones are subject to multiple sources of contamination. Furthermore DNA results are necessarily based on scanty data sources, uncertain provenance, origin and date of the genetic materials. To avoid such problems some  genetic  investigations have based their investigations  on small isolated Tuscan communities which are assumed to have changed little over the millennia  (i.e. Murlo in Tuscany, Italy). The Murlo study suggests that the isolated community in Tuscany has unusual and distinctive  genetic ties to the Near East.  Another source of genetic evidence comes from investigations of cattle breeds in Tuscany. There are four very ancient cattle breeds found in Tuscany. Mitochondrial DNA studies of these ancient breeds, also indicate connections to breeds in the Near East while all other Italian breeds are from northern Europe.

Could the Etruscans have been a mountain folk a  Rhaetian speaking culture from the Eastern Alps or central Europe who at some time prior to @ 900 BC migrated to northern Italy?  The Italian Alps especially in its eastern districts are renowned as a region where copper metal was widely exploited since prehistory. Widespread and abundant occurrence of copper smelting sites and slag heaps are found in the Alps and are dated to the tail end of the Bronze Age.  (See Artioli G, et al; “Eneolithic copper smelting slags in the eastern Alps”, Jour Arch Sci vol 63/ Nov2015, pp 78-83).  

Perhaps Rhaetian speakers from the late Bronze Age,  carrying with them the tools, traditions, knowledge and skills of Alpine copper mining, smelting and metallurgy migrated, not from distant Lydia, but from the near-by eastern Alps into the Apennines. The distance from copper mining regions in the eastern Alps and the early Etruscan site of Populonia in western Etruria  is only some 330 miles ( 528 km ), one in which a band of a pedestrians could complete in a fortnight (14 days (@ 24miles per day).  

These Rhaetian speaking, copper miners may have emigrated from the Alps and entered into the Po valley, seeking mineral resources, woodlands (for essential smelting  fuel) and conditions similar to their homeland. Crossing the Po Valley they could have proceeded into familiar mountainous territory as they entered  northwestern Italy.  There in the area that would become Etruria, they came upon a “ promised land” with rich sources of various mineral ores, especially  among the Colline Metallifere  of Tuscany where rich deposits of copper, iron, lead and silver ores were widespread.  There too, were rich soils  gentle slopes, with abundant water, and excellent  prospects for profitable agriculture.  Furthermore,  this region had extensive forests, necessary for smelting ores that were mined there. It must have been clear to these immigrants that mining and smelting metals could be profitably pursued in this region. 

Furthermore, bordering the mountains on the west, the Alpine immigrants came to the Tyrrhenian Sea, where an extensive and accessible shoreline gave access to  the wider Mediterranean.  This  opened the prospects of foreign trade and interaction with other cultures.  And with trade would come the more intimate exposure and stimulation of new ideas and technology arising from contact with peoples from foreign shores. 

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Based on what we know of the early Etruscans  we  can assume that by the 8^th C BC they were already highly accomplished masters of bronze metallurgy.   That seems likely for a group of people who may have had long experience as miners and metallurgists. In Etruria there were excellent areas to work their trading, mining and smelting crafts in copper and bronze metallurgy and later in iron mining, smelting and trading. 

The Etruscan hilltop site at Populonia on the southern coast of Etruria was one of the most important iron metalworking sites in the Mediterranean, due to the near-by rich iron ore deposits on Elba Island. In a 2005 study, archeologists investigated  deposits of smelter slag on the beach near Populonia, in southern Tuscany which revealed a sequence of stratified slag wastes.  At the base of the sequence, only copper smelting slag occurs. This copper slag is overlain by iron smelting slag higher up in the layered deposits. Radiocarbon dating of carbon fragments in these deposits indicate that the shift from copper to iron smelting took place between the 8^th and early 6^th century BC. 

Other studies have demonstrated that before iron,  copper was smelted at this site, between the 9^th and 8^th century BC. (See: “Copper Metallurgy in Ancient Etruria at Bronze AgeTransition etc., by Chirarantini, L. et al.   Journ Arch Sci Rpts  vol.19, 6/2018, pg 11-23).  (This tends to support the idea of immigrant Rheatian speaking copper miners from easter Alps) . The authors demonstrate,  by use of lead isotope analysis that there is no evidence that early Etruscans used local (Elban or Tuscan) copper ores, since the copper slags from smelting operations at Populonia display a  “foreign Pb (lead) signature” apparently the ancient Etruscans in Populonia were at first involved initially in metal trading  for copper with other regions.  This study suggests that only later did they begin mining copper (and other metals) on Elba and elsewhere.   

It is well established that  by the 6^th century BC Etruscans were actively trading “bloomery” iron and iron bars originating on Elba Island, to regions all over the Mediterranean as well as in central and northern Europe. 

This Greek “diaspora” and colonization began in the early Iron Age and intensified in the 8^th C BC. It  led to establishment of Greek colonies along the shores of much of the Black Sea, and many colonies in the Mediterranean basin.   Greek colonization of many areas of the Mediterranean around 900-700 BC, was probably due to the limited areas for agriculture in the Greek homeland.  Overcrowding, scarce food, limited land and easy acess to marine transport encouraged colonization of other lands. But as producers of ceramics, bronze as well as  artisans and traders the Greeks were in constant need for timber (for fuel) and metal resources.   

In the 8^th C BC Greek settlers from the island of Euboea (off the eastern coast of mainland Greece) established the colony of Cumae in Italy, on the Tyrrhenian west coast, near modern day Naples in Campania.  In @ 600 BC Greeks from Phocaea, an Ionian Island, off the coast of modern day Turkey (Anatolia), founded Massalia (Marseilles, in France),  and also founded Emporion (575BC) just north of modern-day Barcelona in Spain.  

Thus from at least @700 BC the Etruscans were trading with and interacting with Greeks, who they came in contact with all through their many Mediterranean  colonies as well as Greek-established smaller  “emporia” or trade markets founded in the Tyrrhenian Sea, on Corsica and Sardinia, on Ischia and most importantly with the colony of Cumae on the Italian mainland. 

The cultural impact of this trade and interaction with Greek traders had great influences on the Etruscans. One example of this was the adaptation of the Euboean Greek alphabet by the Etruscans to write their language.  The earliest known example of this is a wax tablet found in Tuscany (Grosseto). The tablet had an Euboean-Greek, 26 letter alphabet (no omega), inscribed around the ivory frame. The tablet was dated to 700BC.  So assuming this was a student’s tablet—we can assume that by 700 BC Etruscans must have been literate enough and wealthy enough to have their young students engaged in writing and practicing writing skills with a wax tablet.                   

Etruria was rich in iron ore.  During the Iron Age, mining of iron ores and smelting operations on the island of Elba were legendary. The Greeks famously used the sobriquet “smokey island” ( αιφαλια) for Elba due to the many smelting sites on the island. Mining shafts were very common, and are even today visible. The many smelting sites left vast piles of slag as waste, which are still identifiable today. The other impact was on the island’s forests.  The smelting process required a great deal of wood to make charcoal for the smelting furnaces. Elba was eventually practically denuded of forest cover as a result. 

Smelting was energy intensive.  In the smelting operation local Elba iron ore was crushed to a powder and cleaned of coarse silicate rock. The crushed ore was  placed on top of a charge of charcoal in a small barrel size brick “smelter”. Early smelters were low cylinders constructed of heat tolerant stone or brick with openings at the base for entry of air. In most smelters air was forced into the base by hand operated bellows to raise the temperature of the charcoal fire and generate CO2 carbon dioxide and carbon monoxide CO gas. It was the latter gas, CO, which “reduced”  the iron oxides to impure frothy iron metal called a “bloom” . When the fuel was burned off and cooled down, the smelter was emptied and the frothy iron was removed. 

Bloom iron was impure. It had to be “wrought” or worked to make a usable iron.  Bloom iron came from the smelter mixed with non ferrous brittle slag that had be removed by crushing with heavy iron mallets.  Crushing helped separate the brittle slag from the malleable iron bloom. When this was accomplished the  bloom iron was removed to a forge where it was again heated in a charcoal fire  to a high temperature. When red hot and soft, it was  folded and hammered together again. This heating and folding over and over again (some claim 15 times) was repeated to create a low carbon iron rod called “wrought iron”.  

Such a wrought iron rod could be further heated and hammered or “wrought” into a tool, or weapon, cooking pot or other artifact.  Bloomeries such as described above could produce 3-5  kilograms (6 to 10 pounds ) of wrought iron at a time.  The wrought iron process of heating and hammering reduced the carbon content of the iron. To make tools or weapons, early metal smiths learned that they could heat the iron in a charcoal fire and then quench it in oil or water.  This process added carbon ( @0.002-2%) to the wrought iron and created an outer rind of steel, an alloy of iron and carbon that is harder and stronger than iron. It should be noted that iron smelting required huge amounts of wood and charcoal.

To produce charcoal ancient colliers would enter a forest glade, cut the forest and saw the wood into suitable pieces.  The cut wood had to be dried and then stacked. To make charcoal the stacked wood, often assuming the size of a small house, had to be burned with restricted air or  “smolder”. To accomplish this,  the wood pile had to be carefully sealed and covered with sod or soil to limit air flow.  Small air openings were arranged along the base of the pile to control air flow. Finally, the pile was fired. During firing the charcoal  pile had to be constantly monitored—perhaps for days— so it would only smolder and not flare up into a conflagration—which would convert the valuable charcoal to useless white ash powder .    

Deveareaux, Brett  2020, (“Collections on Wood” https://acoup.blog/2020/09/25/collections-iron-how-did-they-make-it-part-ii-trees-for-blooms) estimates that a Roman legion (5,000 men) in the Late Republic might have carried with them as weapons and tools of @ 50 tons of iron. To make that amount of iron would have required  mining about  600 tons of ore, smelted with @ 710 tons of charcoal, made from @ 5,000 tons of wood.  Or simply to make one ton of iron —you would need 12 tons of ore, 14 tons of charcoal produced from 1000 tons of wood cut from (based on an average NA forest which generates @ 16 cords/or 40 tons of wood) about 25 acres of healthy forest. 

Thus it is clear that the Etruscans must have quickly burned up the forests on Elba and then transferred their smelting operations to the mainland.  

The Etruscans were especially noted for their production and export of iron, as wrought iron bars, and as manufactured products..  We know that in exchange for the iron (based on objects found in Etruscan tombs) they they imported ivory from Egypt,  amber from the Baltic states, and red and black figure Greek vases and pottery.  And with this wide trade came powerful cultural influences which added to the sophistication of the Etruscan culture.  

In the 5th Century BC Etruscan towns began minting their own gold coins in response to the needs of a nation that required the services of others which whom they were not in a trade relationship…such as other artisans, and various services, as well as payment for soldiers.  

So let us give the ancient and talented Etruscans—from wherever they came—the credit for having the ability, the skills, and the energy to develop  the first sophisticated and advanced  culture in Italy, which set the stage for the emergence of Rome— the cradle of our western civilization …And one wonders…did they “invent” pasta too? 

             

GARLIC MUSTARD A WEED FOR ALL SEASONS—

 Garlic Mustard is a weed for all seasons for Long Island walkers and nature enthusiasts. See https://www.foragersfolly.co.uk/garlic-mustard/

Garlic Mustard (Alliaria petiola)a member of the Crucifera (Cabbage or Brassicaceae Family) native to Europe, Asia and Africa. These plants can be observed almost all year round. They are a pleasant accompaniment on winter walks, as the lonely green plants “courageously’ growing profusely almost everywhere among the brown leaves and wisps of dead grasses along almost every privet hedge-line or fence line, evidently undaunted by the frigid temperature. This hedge and fence line habit has encouraged the name “Jack by the Hedge” in the UK.   Garlic Mustard even grows happily under snow cover.  Crush these winter leaves with your gloved hand and notice the garlic aroma. The long root, if you are so inclined to investigate, also has this garlic aroma. 

The  “winter leaves” of Garlic Mustard are dark green, and distinctively shaped like the hoofs of a small calf or colt.  However, when Spring arrives these clumps of rounded crinkly green leaves sprout very early into one-meter tall light green stems  with new and different shaped leaves that are  heart-shaped, deeply toothed,  and with a long stem (petiole) and a sharply pointed tip . the pointed tip seems to be there to direct the droplets of Spring rain straight down to its roots.  The flowers are white with four petals and six stamens (the outer two are shorter than the inner four) arranged in a cross shape, a pattern characteristic of this family. These attractive early, white-flowered, light green, spring plants —like the winter rosettes of colt foot shaped leaves—are found just about everywhere..and particularly —along forest edges and fence lines. 

It is in Spring with  their white flowers and green stems you might notice them again..and identify them as “garlic mustard” by simply crushing the leaves. A distinct garlic aroma is produced.  In Europe there is a tradition of using the plant as a flavoring, particularly as a ingredient in sauces for fish and lamb. The leaves, like most members of this “mustard family” are edible when they are immature (in early Spring) before the flowers bloom. Our British wild food enthusiasts make a Garlic Mustard Mint Sauce, Greek style garlicky “Dolmades” from the leaves, and as a flavorful accompaniment to roasted potatoes, dig the roots for a garlicky horseradish and more. See: https://www.foragersfolly.co.uk/garlic-mustard/ (But I recommend caution when foraging for wild plants…Don’t do it.) 

The Brassicaceae Family has a long history, probably dating to 65 million years ago, when the collision of the African and Eurasian Plate welded Eurasia and Africa together and permitted mixing of animal and plant species. In western Europe the family became widespread across Europe, Africa and Asia….thankfully..it did since they are a wonderfully diverse and useful group of plants.  This particular genus of Garlic Mustard or Alliaria  may not have evolved at that early time or was simply left behind when north America split off from Africa and Europe about 200 million years ago. As a result, it is an invasive plant with few natural insect or biological enemies in North America. 

CULTURAL GEOLOGY OF ROME FOR TRAVELERS: THE SEVEN HILLS OF ROME

 CULTURAL GEOLOGY OF ROME 

ROME, THE ETERNAL CITY AND ITS SEVEN HILLS

An introduction to the geological origin of the Seven Hills of Rome for Travelers.

Rome, “La Cita’ Eterna” is the capital of Italy, the third largest city in Europe and the largest metropolitan area physically dominated by volcanoes in Europe.  It might be accurately called “La citta’ dei volcani” (the city of volcanoes).  Rome’s 500 square mile metropolitan area, In the Lazio region lies in the floodplain of the Tiber River, only 16 miles from the Mediterranean. The City occupies a coastal plain underlain by both intrusive and extrusive volcanics. Volcanoes dominate its skyline.  To the north of the City, lie the Sabatini Volcanic Complex and to the south, the Alban Hills Volcanic Complex.  The Apennine Range a four thousand foot tall, faulted and folded  mountain chain, is found to the east of the City.  The rich volcanic soil, volcanic landforms, and associated igneous rocks,—as well as occasional violent volcanic eruptions— have had enormous impact on the City’s development and its history.   

Rome, a city continuously occupied for nearly three thousand years, has its history intimately tied to seven low hills within the ancient city center.  The famous “Seven Hills of Rome” have played an important part in the founding, development, and history of the City.  Interestingly, we will see here below how these famous landforms (“la collina”) are part of the volcanic history of the region.  Their seven names are legendary:the Capitoline, Palatine, Aventine, Caelian, Quirinal, Viminal, and Esquiline Hills.  These Seven Hills played an important role in the early history, myths, culture and development of the City. 

The Palatine Hill was the site of the legendary founding of Roman City in 753 BC by the mythical and eponymous Romulus and Remus. While the Capitoline Hill served as the first political and religious center of the Republic. Its first “capital” where we get our word for such a place.  The Capitoline was where the most revered religious temple— the Temple of Jupiter was sited. (https://en.wikipedia.org/wiki/Temple_of_Jupiter_Optimus_Maximus).  Today, the magnificent white marble National Monument to Victor Emmanuel II and the Tomb of the Unknown Soldier grace the north slope of this, the smallest of the hills. (See https://en.wikipedia.org/wiki/Victor_Emmanuel_II_Monument)

After almost three thousand years of  human activity and commercial development, the hills, now densely occupied by famous buildings and well vegetated parks,  are not so easily detected.  Even in antiquity, they were only modest hills of perhaps 100 feet (30 meters) above the Tiber floodplain in the Field of Mars.  For modern visitors , the Hills seem to rise only imperceptibly above the surrounding areas, such as the Campus Martius which is only about 30-40 feet (10-12 meters) above sea level.

Rome’s Seven Hills, like many other features in this part of Italy, are the result of volcanic eruptions of the distant past. For Rome these ancient volcanic events  originated in the Alban Volcanic Hills, only 25 miles south of Rome . See: https://en.wikipedia.org/wiki/Alban_Hills ) 

The Alban Hills are a  complex feature of old and new volcanoes, the crests of which can be seen along the southern skyline off Rome from many parts of the City. The Hills form as a series of 3,000 foot peaks visible from Rome. The Alban Hills complex first erupted violently about 600 thousand years ago. Eruptions continued intermittently until the last major eruption of about 20,000 years ago.   They are still considered “active” volcanoes and are monitored closely as a “threat” to the City. . 

Geologists believe that that last great eruption of twenty thousand years ago may have been very similar to the 79 AD Mount Vesuvius event.  Vesuvius, near present day Naples, erupted violently and buried Pompeii in “pyroclastic flows” (https://en.wikipedia.,org/wiki/Pyroclastic_flow), a mixture of fine volcanic ash, pebble and gravel sized volcanic particles called “lapilli”. That ancient city was buried to a depth of  almost 30 feet. 

In very similar circumstances, twenty thousand years ago (20,000 YA) eruptions from Alban Hills poured similar volcanic debris down upon the ancient site of Rome. Geologists have reconstructed flows of pyroclastics which sped down the slopes of the Alban volcanoes into the then unpopulated valley of the Tiber River to partly fill that area with as much as 100 feet (30 m) of volcanic ash and pyroclastics (fine ash, and rock fragments of pebble and cobble size). These deposits hardened into a volcanic rock called “tuff” or tufa. 

After  thousands of years, erosion, flooding and mass wasting much of this rocky volcanic fill, perhaps formed into a  “plateau like” landform, was partially dissected and eroded away by tributary streams of the Tiber River.  After this long period of erosion, only isolated remnants of the volcanic flows remained by the 8th C BC when the area was settled by a Latin tribe. By this time much of the volcanic fill had been washed away by streams and other processes and had taken on the form of seven low hills.  

These volcanic deposits from past eruptions were transformed into the iconic “Seven Hills” of Rome which were to play so important a part in the early history of the  City and the Republic.  

The original hills were no doubt somewhat higher, and were probably vegetated with native trees and shrubs such as the olive, myrtle, laurel, oleander, mastic, Aleppo pine, and cork oak. 

Thus Rome as an early  settlement of of local Latin tribes began among the partly eroded deposits of a 20,000 year old volcanic eruption.  They may have chosen the site for its access to fresh water, hill tops were more secure from threat and safe from flooding, and the general geographic setting afforded protection from invasion. The “hills were partly surrounded on the east and northeast by the meandering Tiber River. To the south, lie the  Enea Hills, and to the southeast, the Alban volcanoes rise up a thousand feet, while the 4,000 foot Apennines dominate  the region to the north and east.  

The Tiber arises in the northern Apennines from springs on Mount Fumaiolo and flows south through the central Italian Apennines passing  through Perugia on its way to Rome. Its course is controlled in this southerly direction by a prominent, elongate geologic fault in the mountains called  a “graben”.  (https://en.wikipedia.org/w/index.php?title=Graben&oldid=1153732450).  In In th evicinity of Rome the Tiber River turns sharply west, passes around the Seven Hills and continues on for 16 miles to enter the Tyrrhenian Sea at Ostia.(See: https://en.wikipedia.org/wiki/Tiber ).  

During the geologic process which formed the Apennines east of Rome some 23 MYA, a portion of the Earth’s crust was subducted (settled)  into the hot mantle.  The sinking process tended to“pull” the descending crust downward and caused  the slab of descending crust to “stretch”. The results of this stress were faults or cracks in the slab of descending crust. This resulted in the formation of a form of “dropped  block fault” or graben—literally a “trench” into which the Tiber River naturally followed. The stretching and faulting of the earth’s crust produced  this near-straight-line graben or trench resulting in the near linear course of the Tiber River in this area..   

Just north and east of Rome, the River leaves the graben and turns sharply southwest where it is joined by its tributary, from the east, the Anio River. From there, the river flows southwest through Rome, past its ancient port city of Ostia. Over the near 3000 years since the founding of the City and the accumulation of seiment at the mouth of the River, the port of Ostia is now several miles inland from where it originally  entered the Tyrrhenian Sea. 

The Tiber was an important source of fresh water for the early Romans as well as a means  of essential  transport and trade for its later occupants.  And as not above it also served as a protective barrier during the early history of the City.

In its lower reaches the Tiber is a meandering stream. (See wikipedia “meander” https://en.wikipedia.org/wiki/Meander). Such twisting and turning of the stream bed or “meandering pattern” is characteristic of a  very gently sloping river-bed and slow current. 

This may be the result of the fact that over the last 10,000 to 12,000 years, sea level has been slowly rising as a result of post glacial warming. As sea level rises it, in effect, reduces the slope of a river.   As slope decreases, the force and speed of the flow of water in the river bed is reduced. Rivers with slow currents cannot erode their beds effectively, and begin a process of lateral erosion, or widening their flood plains by eroding and sediment deposition of their banks.  This process causes the stream bed to move laterally across its flood plain in a twisting circuitous pattern called “meandering”. 

This characteristic meandering  flow of the Tiber served as an advantage to the early Romans, since this curving course of the River partially enclosed the Seven Hills and became an important aspect of the area’s security from invasion. ( See: https://en.wikipedia.org/wiki/Meander ).

Early inhabitants had the dual advantages of protection from invasion, as well as an abundant  fresh water supply.  Furthermore, the seven hills “hilltop” occupation made attack by enemies from low ground more difficult and added this element of protection from attack.  

The Tiber  was subject to regular seasonal flooding. This no doubt increased the fertility of the meadows and swampy terrane between the Seven Hills.  In addition to the fact that the soils in the low lying areas were naturally rich in minerals as a result of their volcanic origin, but the annual floods of the Tiber added to that fertility by deposits  silt and organic materials each year which improved agriculture. On the other hand, the hills  protected residences and structures of early settlers  from these seasonal floods.

The volcanic origin of the Seven Hills had other advantages as well. As noted above the Seven Hills and the entire region is underlain with volcanic deposits from past eruptions. The local volcanic bedrock known as “tuff” besides contributing to the fecundity of the soils also happens to be a useful and easily mined and shaped construction stone (See:https://en.wikipedia.org/wiki/Tuff )  

Tuff is an igneous rock composed of volcanic ash and coarser volcanic derived particles welded together into a soft gray or brown rock. The local gray-brown variety in Rome is known as “Cappellacio Tuff”.  This rock was deposited on the slopes of the Alban Hills and also in areas around Rome. It formed the bed rock of the Seven Hills during the eruptive stages of the Alban volcanic complex . Ancient Romans and Etruscans extensively quarried this Cappellacio Tuff as a widely available, easily quarried, useful building stone. There are extensive quarries at various sites in the Alban Hills.  

The oldest walls in Rome, are the Servian Walls (built in the 4^th C BC). The walls are often claimed to have been constructed as a protective barrier after the attack Rome by Gauls in 390 BC.  But it seems that is uncertain.  The original wall was built sometime in the sixth century BC (500s BC) by the Servius the King of Rome at the time, using the local gray or light brown available Cappellacio tuff as a building stone.  A section of this ancient wall is still extant and visible just outside of the central train station in Rome. Tuff  is relatively soft and can be easily cut and shaped. The Romans cut the Cappellacio tuff as well as many other types of rock into isometric rectangular blocks for a type of  construction called “ashlar construction” widely used in many places in Rome. Keep your eyes open for rock walls with roughly shaped stone blocks—not—cemented together.  

But after the Gaul attack of 390 BC the existing rock walls were considered insufficient and were added to or replaced using a harder more resistant yellowish stone called Grotta Oscura tuff.  Grotta Oscura became available after the 390s BC after the Romans had defeated the Etruscan City of Veii.  The Romans simply had the Veiians deconstruct the protective wall around the defeated city of Veii and forced the Etruscans to transport the blocks to Rome.  (See:  https://en.wikipedia.org/wiki/Servian_Wall ). Later they also quarried the Grotta Oscura tuff from Etruscan quarries as well.