The Terni area has yielded archeological findings going back to the Neolithic, but its famous and impressive necropolises, holding two thousand tombs with a rich store of burial objects, are among the most important relics from prehistoric times. The findings thus provide evidence of a very large settlement, going from the Iron Age to the 7th century BC. Standing out in importance among later settlements is the imposing sanctuary built at the top of Mt. Torre Maggiore in the 6th century, later monumentalized by the Romans. The Roman city, which occupied the same site as modern Terni, was delimited by a circuit of walls built in the 3rd century BC, of which many traces remain. The most important monument in the city is the amphitheater, built according to an inscription in 32 AD and only partially preserved. Not far away is the theater, the structure of which can be discerned from the buildings that have incorporated it. Recent excavations have also unearthed traces of other public and private buildings.
The Roman place name Interamna Nahars – present-day Terni – refers not only to its geographic position, but also to the Naharkus, an Umbrian people living in the Terni basin and mentioned in the Eugubine Tablets. Cited in many literary sources and epigraphs, the town is characterized by an abundance of water, fertile land and important natural routes, which has encouraged human settlement since prehistoric times in the entire Terni basin. The valleys of the Nera, Serra, and Velino rivers also linked the area to the central Italian territories of the Adriatic, the Sabines, the valleys of the Tiber River, southern Etruria, and Rome. During the Middle Bronze Age (16th-13th centuries BC) the area was inhabited by an animal-grazing, transhumant people, who dwelled in scattered huts and caves. Evidence of their cheese-making activities is provided by the pottery used for this purpose found near Titignano, Avigliano Umbro and Narni.
With the dawn of the Iron Age (10th century BC), the area grew in importance, as can be seen from the large Acciaierie necropolis. Permanent organized settlements formed in this period, a fundamental support for the development of the Terni culture, one of the most important in proto-historic Italy.
The advent of the Orientalizing culture (7th cent. BC) accentuated later development in the area, as seen by the abundant archeological data coming from the San Pietro in Campo and Alterocca necropolises. The most recent excavations near Maratta Bassa and in urban centers have provided evidence that the process of proto-urbanization occurred much earlier here than in other parts of Umbria. In the mountain zones a system of upland settlements also developed; the most significant of these, Sant’Erasmo di Cesi, has vast walls made of polygonal blocks. But the political-religious center of the entire system appears to have been the sanctuary at Mt. Torre Maggiore, built in the 4th century BC.
The Terni area came under Roman influence at an early stage, when Rome began planning the conquest of central-eastern Italy in the mid-4th century BC. The subsequent founding of colonies and the opening of the Flaminian Way in 220 BC marked the definitive submission of the Umbrian peoples to the power of Rome.
Many materials found in the area are on display at the Terni archeological museum, which opened recently.