Archaeology or archeology (from the Greek ἀρχαιολογία, composed of the words ἀρχαῖος, “ancient,” and λόγος, “discourse” or “study”) is the science that studies past civilizations and human cultures and their relationships with their surroundings through the collection, documentation, and analysis of the material traces they left behind (architecture, artifacts, biological and human remains).
Origin and evolution of archaeology
Intended by Plato in the meaning of history of the origins of a people or a city, returned in vogue in the seventeenth century to indicate the study of all ancient documents, limited by the nineteenth century to non-literary monuments, the term archaeology indicates the science that studies the historical evidence of cultures and civilizations – as well as settlements or deposits, land and underwater – known or knowable mainly through the discovery of material remains. Therefore do not fall in the field of archeology paleontological deposits (unless they are not related to the appearance of man), while archeology extends beyond the ancient age and, in non-European continents, until the colonial age.
With the term archaeology, without other specifications, we commonly mean the so-called classical archaeology, which studies the civilizations of the Mediterranean peoples, and in particular of the Greeks and Romans, until the threshold of the Middle Ages. However, archaeology can also be prehistoric (or palethnology) or medieval, or even industrial; or, in relation to the location of ancient remains, eastern, northern, African, American, etc..
The term Christian archaeology usually means the study of Christian monuments from the origins to the first centuries of the Middle Ages. The first archaeologist, understood as a researcher of ancient monuments, can be considered Ciriaco de ‘Pizzicolli (travel in Greece between 1412 and 1448), while J. J. Winckelmann was the first to give an artistic interpretation, as well as historical, monuments of classical archeology (Geschichte der Kunst des Altertums, 1764; History of the art of antiquity).
In the nineteenth century, scholars became more interested in works of figurative art, with particular regard to the masterpieces of the great masters (A. Furtwängler). In the twentieth century the two disciplines, archaeology and history of ancient art, complement each other, developing a historical interpretation of the various periods of the cultures examined. To conduct its investigations, contemporary archaeology uses many other disciplines, such as philology (for the knowledge of the sources), topography, epigraphy, numismatics and, since the last decades of the twentieth century, even modern technology in relation to excavations.
In order to identify archaeological remains without carrying out excavations (this is the purpose of archaeological prospections) the most widely used system is that of aerial photography. In particular conditions of season, soil humidity, state of the crops, the photograph shows both the course of the ancient walls (above which the vegetation is usually sparser and the ground takes on different shades) and the cavities, such as prehistoric ditches (where the vegetation grows more luxuriant).
The stereoscopic examination of several aerial photographs of the same area is then linked to data taken from other sources (historical information, excavation essays) in order to arrive at an aerophotogrammetric restitution of the area. Aerial surveys have made it possible to reconstruct the course of the Roman limes in many regions of Africa and Asia, to identify prehistoric settlements, to reconstruct the layout of archaeological centers and to determine the route of ancient roads.
Electrical prospecting is based on the alterations that the resistivity of the ground may undergo in correspondence of ancient walls and cavities. The method, used in Italy and abroad since about 1950, has given interesting results in Etruscan necropolis.
Magnetic prospections are based on the measurement, generally by means of proton magnetometers, of the intensity of the magnetic field of the ground, which can vary when ancient remains are buried in the soil: the elaboration of the numerous data obtained with this method, the most widely used, is carried out with the use of electronic calculators.
The geochemical prospections identify the remains according to the quantity of phosphorus in the soil exceeding the norm, due to ancient settlements. Less usable are electromagnetic prospections and those with gravimetric instruments (useful for the identification of large cavities), while further investigation requires other methods of prospecting based on radioactive systems, polarization effects, infrared radiation.
At the limit between prospecting and excavation are stratigraphic prospections, which consist in making holes in the ground by means of special rotating probes, which identify the archaeological materials buried in the different layers.
Archaeological dating methods
In addition to the traditional methods, based either on the comparison of the object to be dated with others already known, or on its origin from more or less deep layers (relative dating), absolute dating systems have been developed, the best known of which is the radiocarbon method (W. F. Libby, 1947). The method is useful for carbon-containing substances (charcoal, dry wood or peat, shells, burnt bones) and has proved especially important, despite possible errors, for dating prehistoric materials up to 50-70,000 years ago.
Obsidian artifacts can be dated based on the depth of water penetration within the artifact itself; similarly, based on the thickness of the encrustations, glass objects can be dated. The age of the bones can be determined, although with considerable uncertainties, based on the amount of fluorine absorbed by them.
The dating system based on paleomagnetism (or archaeomagnetism, or residual magnetism) is based on the observation that the earth’s magnetism varies in direction and intensity and that objects containing even small amounts of substances sensitive to magnetic influence (ceramics, furnace residues, raw brick walls subjected to a fire) retain the magnetism of the time when the firing took place.
Dendrochronology is based on examining the progression of plant growth circles, which is similar for all trees in the same region in relation to rainfall conditions. In the United States, continuous seriations have been obtained up to ten centuries ago, which has made it possible to know the exact year in which the trunks of ancient buildings were cut and thus to determine the age of the villages.