Geography and the history of Terni
The geographical situation of the ancient area of Terni was delineated by G. Bradley, a scholar of the territory, who said: “Interamna Nahhars lay at the eastern edge of an important plain, known today as 'Conca Ternana'.
Overlooking the plain are two of the great southern Umbrian Massifs, Monte Torre Maggiore to the north and Monte San Pancrazio to the south, whose peaks held sanctuaries from at least the fifth century BC.
These mountains determined the course of communucations into and out of the 'Conca Ternana', which probably always formed a vital crossroads in southern Umbria. Interamna Nahars itself was almost completely surrounded by the course of two rivers, which came together at this point. (See also the etymology of Terni further down this page.)
One of the rivers was the Nar, a fundamental feature in the geography of the area” . P. Renzi, an expert on the ancient history of Terni, after observing that the territory of Terni was the site of prehistoric settlements, stresses that the ancient village developed at the convergence of the stream of Serra and the Black River, and that it was a thriving community and open to trades.
When the city was Romanized, in the mid-third century BC, it took the Latin name of 'Interamna'. The classical authors were very clear and explicit in this regard: 'The cities named "Interamna" are so called because they are situated between [two] rivers] (Paul the Deacon [720-799 AD]).
The Latin term 'amnis' indicates a particular type of river: “the term 'amnis' means a river that surrounds something; in fact, 'amnis' derives from the term 'ambitus', that is circular movement (ibid. Varro)]. ‘Amnis’ therefore differs from the simple term 'Flumen' or 'fluvius' for its sinuosity, but the expression usually indicates also the abundance of water.
Therefore, Interamna is the proper denomination for cities that are located between the running and surrounding rivers. In Italy similar cases are known with regard to 'Interamna Praetuttiorum' (=Teramo) and 'Interamna Lirenas' (near Cassino) .
Roman development of Terni
The foundation of Interamna was part of the process of Romanization of Umbria in the early third century BC that took place in the context of the drainages performed by Manius Curius Dentatus (330-270 BC). The city was crossed by the Flaminia Road and it benefited a lot from the country's trade.
Interamna, according to tradition, was an important "Municipium" [a Roman city of the second highest rank], equipped with an amphitheater, a theater and also walls, whose remains were recently discovered, and it had some gates, of which traces remain today, but which presumably coincided with the medieval walls.
The problem of the birth of the "Municipium" of Terni has been the subject of much discussion: “M. Fora revisits the problem of the municipal status of Interamna Nahars, a topic of relevance to our interpretation of the Romanization of Umbria, and argues that it became a municipium only in the aftermath of the Social War. He contends that the decisive piece of evidence is a cippus relating to a border dispute (CIL XI.4806a).
If this is associated with Interamna Nahars rather than Spoletium, it demonstrates that the town could not have been a municipium already at the end of the second-early first century BC because it would not in that case have had its dispute resolved by external judges” .
The most important Roman remains are located to the south and are represented by the theater and amphitheater, while to the south-east were found the remains of patrician houses ("Domus") near the Roman church of St. Saviour. In San Angelo some remains of the baths have been identified. During the Imperial age Interamna surely had a period of significant development, as demonstrated by the theater and the amphitheater.
The latter, according to careful studies of D. S. Pirro, was decorated with the technique caled “opus reticulatum”, a technique that was very difficult to perform especially if the work was made of extremely hard materials and difficult to shape; the “opus reticulatum” consisted of a series of pyramidal 'cubilia' [tufa blocks] , with measures ranging from 5 to 7 cm, assembled with mortar to improve the joints. This technique was very difficult, and was later abandoned for other simpler techniques .
According to Bollough, Christianity became established around 305 AD in Umbria and one of the first Christianized cities was Terni . The achievement of Christianity here was quite slow and imbued with many events which are purely legendary, such as the first figure of the Bishop San Brizio (first century AD), while the figure of Sant'Antimo seems definite (second century AD).
After the Romans...
With the end of the Roman Empire, Terni, like all the Umbrian cities along the Flaminia Road, was a city exposed to the incursions and depredations of the Goths and the Byzantines, though it does not seem that it had been completely destroyed, as a secular tradition said:
“With regard to the early Middle Ages, one of the most deep-rooted ideas in the history of Interamna Nahars is the complete destruction of the city that suffered by barbarian tribes that arrived in Italy between IV and VI century AD" .
Another epochal moment in the history of the city was the conquest by the Lombards and the inclusion of Terni in the powerful Duchy of Spoleto. The 'donation of Sutri' of 728 and the 'peace of Terni' of 742 marked an understanding between the Lombards and the Papacy.
Pope Zachary (died in 752) entered into private negotiations with Liutprand (690-744). The Pope met Liutprand in Terni in 742, obtaining the restitution of the papal estates and the withdrawal of the troops from some important cities. After the Lombard domination, the territory was subject to raids in 800 by the Saracens and then in 900 to raids by the Hungarians.
In the eleventh century Terni was largely ruined by the troops of Frederick Barbarossa (1123-1190), who later enfeoffed the city to Octavian Monticelli and his brothers and its territory.
Innocent III (1160-1216) sanctioned Terni as a free Commune with a brief of April 16, 1198: “Four months before the election Frederick had conferred on Octavian's brothers, as an imperial fief, the city and county of Terni, which the papacy claimed as part of the Patrimony of St Peter .
As a free municipality, the Bishopric of Terni was restored by Honorius III (1148-1227) in 1218: “The agreement with the Papacy secured benefits for Terni, to which corresponded a great fervor in new building. In the framework of the State of the Church, set by Innocent III and pursued by his successors, the position of the city took an important role as a buffer zone among the surrounding towns (...)
The support of the Popes, such as Innocent III and Gregory IX (1170-1241) contributed to the growth of the city which culminated with the establishment of the Diocese (1215-1218) and the enlargement of the territory, with the conquest of the castle of Papigno and towers along the borders .
In general we can say that the cities of the State of the Church enjoyed more or less wide municipal liberties. However, for centuries Terni was included in the domains of the Papal States, with conflicting relationships with the Papal Vicars.
Terni from the 13th century
Although we can not deny that the first decades of the 13th century were for Terni, governed by established local institution, a period of political and economic success, the presence of the Papal Vicars was suffered only with extreme difficulty, as the city pursued its own autonomy, until the action of Cardinal Albornoz (1310-1367) - he intervened in Terni, where "he favored the return of exiled Guelphs and obtained a revision of the statutes."
Consequently, the impatience of Terni against the Papal Vicars was always very high. An example is constituted by the destruction of the “Rocca” [fortress], built by the Popes "ad servitium Romanae Ecclesiae", [in support of the Roman Church] which was "rebuilt in 1436, but then finally demolished by the inhabitants of Terni, who could not tolerate the interference of the papal government in the affairs of the city" .
The papal authority was not able to control the extreme litigiousness of the cities, as demonstrated by the revolt of the so-called "Banderari" (middle class), who in August 1564 massacred some members of the nobility. This was due to the fact that the nobles, with the support of the Pope, promulgated in 1562 an "institutional reform against the “Banderari”, an office which since 1398 had been chosen from among the representatives of the bourgeoisie (...)
With these reforms, they were forbidden to bear arms, to meet without the consent of the Priors, and to communicate independently with senior officials and dignitaries. On the night of 22 August 1564 the ‘Banderari’ retaliated by killing 14 members of local noble families (Ranieri, Manassei, Gigli and Mazzancolli) .
Pope Pius IV (1499-1565) reacted very harshly, and with the help of the nobles deprived the City of all autonomy and submitted it to the authority of a Vicar sent from Rome. The 16th and 17th centuries saw action in Terni by some men of power who were strongly linked to the Papal Court, like Michelangelo Spada (born in 1521), chamberlain of Julius III (1487-1555), and at the same time well deserving of the arts, because he brought artists such as Sangallo to Terni.
Terni from the 17th century
From a political point of view, the Umbrian fragmentation also continued in the 17th century, ending only with the advent of Napoleon I (1769-1821). The advent of the French broke the centuries-old static institutions of Terni, leading to territorial changes that tended to a more uniform administration of the territory, which was unified in the “Dipartimento del Trasimeno.”
After the annexation to the Kingdom of Italy in 1861 the Umbrian economic life was characterized by agriculture; however, since 1880 things change especially in the territory of Terni:
"The birth of the steel industry in the area of Terni occurred around the 1880 and represented a deep break with regard to the traditional characteristics of the local economy (...) and helped to differentiate this area from the rest of the region, thanks to the formation of an industrial proletariat and to social behavior and political dynamics against the State and the Church, with the phenomena of heated anti-clericalism” 
The industrial growth in Terni was an epochal moment in the history of this small town: "Around the middle of the 19th century the area of Terni was still dependent on a predominantly agrarian economic and social structure, characterized by sharecropping, disinterestness of the owners, and fragmentation of the property."
However Terni had something that other areas did not possess, "the great abundance of water." The industrial fate of Terni was decided at the beginning of 1870 “when the Minister of War, in November of 1872, proposed to install in Terni a weapons factory, obtaining the approval of Parliament (...) Admiral Benedetto Brin and his team of the Navy Department decided to proceed with the launch of a modern combat fleet."
The choice of Terni was due to two logistical factors: the waterfall [Marmore waterfalls cascade], which operated the machines, and the security of the site. What is certain is that the industrial development initially caused Terni a series of dramatic problems: "In a few years the inhabitants of Terni doubled (...) The thousands of working families flocked to the site from all over Italy exceeding the modest accommodation possibilities of the small town", with very serious social consequences .
Today Terni presents a various urban reality, in a natural setting of great charm based around the Marmore waterfalls cascade.
Origins of the name and etymology of Terni
G. Semeraro, writing about the name of Terni, observed that "Terni is the ancient 'Interamna Nahars', on the Nera River on the eastern edge of a large and flourishing valley, rich in water. It has in 'Nahars' the transcription of the name of its river, which at the beginning was the generic Semitic name ‘Nahar’ (trans: river, 'Fluss’) 
In fact, the meaning of "Interamna", an ancient colony founded by the Romans, has to do with water and rivers. Therefore "Interamna" derives, according to a tradition dating back to Gaius Terentius Varro (3rd century BC), from the Latin "inter amnes" (trans: city between two rivers). However, solving the problem of the meaning of Interamna has became very complicated over the years.
Some scholars assume that "Interamna" is the Latin translation of the ancient Umbrian term "termnu", meaning "house" or "village". For example, E. Giammarco writes: "The name 'Interamna (...) derives from the Sabellic language 'en' (Latin 'in') and 'tremnu' (Greek 'tèremnon' = home ")" . If this hypothesis has any foundation, it is evident that the etymology of "Interamna" (and then of Terni, which derives from it) would be "home" or village.
The issue has aroused much discussion, and the "defenders" of the traditional etymology put forward arguments of considerable interest, of which we offer here a brief summary.
We start from the observation that "Interamna" in Umbria was always accompanied by "Nahar" ("Interamna Nahar"). In this regard, A. Prosdocimi observed that "Nahar" is a linguistic "secondary" element because it indicates that the city is situated on the River Nar (now Nera), and above all it serves only to distinguish the city of Interamna, located in Umbria, from other cities that bore the same name, such as Interamna Lirenas, Termini sul Liri and Interamna Praetuttiorum, Teramo:
"Nahart is the title of 'Interamna’; it was given to modern Terni to distinguish it from the neighboring city called 'Interamna Praetu(t) iorum', the modern Teramo" .
In addition, the real toponym is "Interamna", which means "city situated between two rivers" (Terni is situated at the confluence of the Serra stream with the Nera River): "Interamna is a 'speaking' toponym, so called because it is located between two rivers" .
Regarding this point it is important, if not decisive, to note the fact that the ethnic name 'Na (ha) rt' is a 'secondary' term with regard to 'Interamna', which, since it indicates the city, provides the city name and the name of the inhabitants - that is, 'Interamnates' [inhabitants of Interamna].
This fact is confirmed by the inscription indicating the name of the 'civitas' (community) of the 'Interamates' (inhabitants of Interamna); the base name is the 'city', just called 'Interamna' 
On the question of a possible Umbrian "mediation", for which Interamna would derive from "tremnu", Renato Gendre said: "There is no doubt therefore, that the two modern toponyms [that is Terni and Teramo] derived from Interamna with proparoxytone accentuation, which is explained by the 'positio debilis' of the penultimate short syllable (In-tè-ram-na).
An alternative hypothesis is that Interamna is a Latin adaptation of an Italic word related to the Umbrian ‘Termnu’ '(tabernaculo) and the Greek ‘teramna’, ‘teremna’ (=homes') derived from the Osco-Umbrian ‘trebùm’ ['domum'=house]. According to Renato Gendre it does not seem that we can accept the assumption of Ernesto Giammarco, who proposed for Teramo a ‘Sabine mediation' for which we would have the sequence Trebnu > Tremnu> Teramum >Teramo" .
If we understand the subject of R. Gendre, the solution that he offers is very interesting, both because he claims that Interamna is a Latin term that doesn’t seem to be suffering from Umbrian mediations ("tremnu"), and because he derives the modern name of Terni "directly" from “Interamna.” In fact, R. Gendre points out that “In-tèr-am-na” is a proparoxytone word, that is, it is stressed on the third from last syllable [In-tè-ram-na], while the "a" of the penultimate syllable is a short syllable [In-tè-ram-na]; being short, the vowel is usually subject to being dropped in the Romance languages.
In essence, in the transition from Latin to Italian, first the term “In-tè-ram-na” would lose the initial "In", and only “Teramna” would be left; then would fall also the “a”, for which we get "Te-r-mna, which could not "survive" in popular pronunciation, so the "m" would fall and only "Ter-na" would remain. From "Ter-na" to "Ter-ni" the transition is easy.
In fact Prosdocimi suggests a locative: "The final 'i' of 'Tern-i' is likely a locative plural, as in many place names, including 'Narn-i'" . Although the linguistic steps may seem laborious, in reality the loss of letters and syllables in the passage from Latin to Italian (and in the Romance languages in general) was a common occurrence. In this way the ancient etymology of the city is preserved.
Since, according to cited scholars, Terni is derived from "Interamna", it is clear that the modern name means (much as the ancient name) "city between two rivers".
In this way the reference to the Osco-Umbrian term "termnu" is avoided, and consequently the meaning of "house" or village. In our opinion, the ancient etymology fits better to the topography of "Interamna" and at the same Umbria, a region rich in rivers and waters. For all these reasons, we believe that the traditional etymology grasps the truth, because "Interamna" is a very common name in Italy, and all toponyms have a clear relationship with the rivers.
Finally, for completeness of information, we should mention another assumption which is proposed by Giovanni Reccia, according to whom Terni "might" derive from the word "Ater" (= black, dark): "Also the name of Terni seems to be derived from '(a)ter' ... (Is there a relationship between Nahar and Ater?)" .
This relationship may also exist; however, if the considerations of Prosdocimi are correct, the real name of Terni is "Interamna" and not "Nahar", which would be only a "secondary" element next to the name to distinguish it from other cities.
On the contrary, G. Reccia considers it possible that "Nahar" was the real toponym, because G. Devoto pointed out that "the Umbrian territory bordering the River Nera was one of the first to be inhabited by some Proto-Villanovan people called ‘Naharani-Naharti’”  . However, we must remember the fact that the most recent contemporary studies are very doubtful about the existence of the "Naharti".
In this regard, P. Renzi writes: "We cannot call into question any historical source and literary evidence with regard to the existence of the so-called 'Naharti'. The only faint echo that remains of their ancient presence in Latin literature (aside from some local Roman inscriptions mentioning the Latin name of Terni) is found only in the first millennium AD (‘Interamnentes Cognomine Nartes’ [Interamnates called Nartes]) in Pliny (23-79 AD) [Nat. Hist.]."
The fact that the "Naharti" were mentioned only in late inscriptions of Roman times and in the work of a single Latin writer who lived at least two thousand years after the alleged existence of the "Naharti", constituted no conclusive evidence because we can assign a toponym to a people who presumably lived a thousand years before Christ and whose first existence was documented only in the "Tabulae Iguvinae":
"In consequence of the terms used in the text of the ‘Tabulae’, it 'seems' that the Naharti were among the leading peoples of central Italy in the mid-first millennium BC. However, we do not have enough information to determine which was the territorial extension of them." .
It seems certain that the Naharti derived their name from the river Nar (= Italian ‘Nera’): "The historical name of the inhabitants of these lands was ‘Nahartes’ or ‘Naharci’, derived from the name of the Nera River and certified in the ‘Tabulae Iguvinae’ (" Naharcer= ai [to the] Naharci)" . Faced with this uncertainty, it is reasonable to persist in the traditional etymology, by which Terni derives from "Interamna" and means "city situated between two rivers."
See Terni for a travel guide and more information
1. See G. Semeraro, “Le origini della cultura europea”, Olschki, 1984, Part II, p. 623
2. See E. Giammarco, “Storia della cultura e della letteratura Abruzzese”, Edizioni dell'Ateneo, 1969, p . 8 and footnote
3. A. Prosdocimi,“Etnici e 'nome' nelle Tavole iguvine”, in “ Gli umbri del Tevere: atti dell'VIII Convegno internazionale di studi sulla storia e l'archeologia dell'Etruria”, edited by G.M. Della Fina, Quasar, 2001, p. 72
4. Varro, 11 V, 28
5. See A. Prosdocimi, “Etnici e 'nome' nelle Tavole iguvine”, in “ Gli umbri del Tevere: atti dell'VIII Convegno internazionale di studi sulla storia e l'archeologia dell'Etruria”, edited by G.M. Della Fina, Quasar, 2001, p. 70 footnote 1
6. See Renato Gendre, “Note di toponomastica italiana”, in "Linguistica", 1992, n.32, p. 135
7. Prosdocimi, p. 73
8. See G. Reccia, “Topografonomastica e descrizioni geocartografiche dei casali atellano-napoletani di Grumo e Nevano”, Istituto Geografico Militare, Firenze, 2009, p. 111, footnote 230
9. Reccia, p. 111 note 230
10. See P. Renzi, "Terni dalla prima età del Ferro alla conquista romana" in “Interamna Nahartium: materiali per il Museo archeologico di Terni”, edited by V. Pirro-V. Leonelli, Terni, 1997, p. 87
11. See G. Colonna, “Gli Umbri del Tevere”, 2001, pp. 9-20; p. 20
12. See G. Bradley, “The Colonization of Interamna Nahars”, in “Bulletin of the Institute of Classical Studies”, 2000, p. 3
13. See p. Renzi, “La nascita dell'antica 'Interamna'...”, in “La Pagina”, ottobre 2003, p. 5
14. See M. Fora, in “Supplementa Italica”, 2003, n. 19, pp. 23-27; See AA.VV., “Roman Inscriptions”, in “Survey Article”, 2001-2005, p. 184
15. See S. Manzoli, “Terni-Interamna: note sulla topografia e urbanistica della città antica”, in “Architettura e pianificazione urbana nell'Italia antica”, Rome, 1997, pp. 83 ff.; for masonry techniques See D.S. Pirro, “Le tecniche murarie romane nell'Umbria meridionale”, in “Restauro archeologico”, edited by C. Nenci, Alinea, 1988, pp. 108 ff.
16. See A. Melelli-M.A. Petrucci, “Spiritiualità e ambiente...”, in “Itinerari del sacro in Umbria”, edited by M . Sensi, Octavo, 1998, p. 130
17. See S. Zampolini Faustini-C. Perissinotto, “Per lo studio delle città a continuità di vita: " Interamna Nahars " (Terni) fra antichità e medioevo”, in “Studi Medievali”, Chiantore, 1998, p. 576
18. Vedi Ian Stuart Robinson, “The Papacy 1073-1198: Continuity and Innovation”, Cambridge University Press, 1990, p. 474
19. See C. Angelelli-L. Bonomi Ponzi, “Terni - Interamna Nahars”, 2006, p. 569
20. See C. Angelelli-L. Bonomi Ponzi," Terni - Interamna Nahars ", Ecole française de Rome, 2006, pp. 281-289
21. See Comune di Terni, “Il Palazzo di Michelangelo Spada in Terni”, 1997, p. 16
22. See M. Tosti, “Chiesa e questione sociale in Umbria alla fine dell'Ottocento”, in “I tempi della 'Rerum Novarum'”, Rubbettino, 2002, pp.. 497 ff.
23. see G. Zalin, “Grande industria e società a Terni fra Otto e Novecento”, in “Economia e storia”, Milano, Giuffre, 1984, No 3, pp. 376-378