The second phase began in 1925 with the commencement of American excavations at Yorgan Tepe (ancient Nuzi), 140 miles north of Baghdad, a provincial centre with Old Akkadian, Old Assyrian, and Middle Assyrian/Hurrian levels. There followed, among others, French excavations at Arslan Tash (ancient Hadatu; 1928), at Tall al-Aḥmar (ancient Til Barsib; 1929–31), and above all at Tall Ḥarīrī (ancient Mari; 1933 onward) and American excavations in the Diyālā region (east of Baghdad), at Tall al-Asmar (ancient Eshnunna), at Khafājī, and at other sites. Thus, excavation in Mesopotamia had moved away from the capital cities to include the “provinces.” Simultaneously, it expanded beyond the limits of Mesopotamia and Susiana and revealed outliers of “cuneiform civilization” on the Syrian coast at Ras Shamra (ancient Ugarit; France, 1929 onward) and on the Orontes of northern Syria at Al-ʿAṭshānah (ancient Alalakh; England, 1937–39 and 1947–49), while, since 1954, Danish excavations on the islands of Bahrain and Faylakah, off the Tigris-Euphrates delta, have disclosed staging posts between Mesopotamia and the Indus valley civilization. Short-lived salvage operations have been undertaken at the site of the Assad Dam on the middle Euphrates (e.g., German excavations at Ḥabūba al-Kabīra, 1971–76). Italian excavations at Tall Mardīkh (ancient Ebla; 1967 onward) have yielded spectacular results, including several thousand cuneiform tablets dating from the 24th century bce.
In its third phase, archaeological research in Mesopotamia and its neighbouring lands has probed back into prehistory and protohistory. The objective of these investigations, initiated by American archaeologists, was to trace as closely as possible the successive chronological stages in the progress of man from hunter-gatherer to settled farmer and, finally, to city dweller. These excavations are strongly influenced by the methods of the prehistorian, and the principal objective is no longer the search for texts and monuments. Apart from the American investigations, Iraq itself has taken part in this phase of the history of investigation, as has Japan since 1956 and the former Soviet Union from 1969 until the early 1990s.
Finally, the fourth category, which runs parallel with the first three phases, is represented by “surveys,” which do not concentrate on individual sites but attempt to define the relations between single settlements, their positioning along canals or rivers, or the distribution of central settlements and their satellites. Since shortages of time, money, and an adequate task force preclude the thorough investigation of large numbers of individual sites, the method employed is that of observing and collecting finds from the surface. Of these finds, the latest in date will give a rough termination date for the duration of the settlement, but, since objects from earlier, if not the earliest, levels work their way to the surface with a predictable degree of certainty or are exposed in rain gullies, an intensive search of the surface of the mound allows conclusions as to the total period of occupation with some degree of probability. If the individual periods of settlement are marked on superimposed maps, a very clear picture is obtained of the fluctuations in settlement patterns, of the changing proportions between large and small settlements, and of the equally changeable systems of riverbeds and irrigation canals—for, when points on the map lie in line, it is a legitimate assumption that they were once connected by watercourses.
During the four phases outlined, the objectives and methods of excavation have broadened and shifted. At first the chief aim was the recovery of valuable finds suitable for museums, but at the same time there was, from early on, considerable interest in the architecture of Mesopotamia, which has won for it the place it deserves in architectural history. Alongside philology, art history has also made great strides, building up a chronological framework by the combination of evidence from stratigraphic and stylistic criteria, particularly in pottery and cylinder seals. The discovery of graves and a variety of burial customs has thrown new light on the history of religion, stimulated by the interest of biblical studies. While pottery was previously collected for purely aesthetic motives or from the point of view of art history, attention has come to be paid increasingly to everyday wares, and greater insight into social and economic history is based on knowledge of the distribution and frequency of shapes and materials. The observation and investigation of animal bones and plant remains (pollen and seed analysis) have supplied invaluable information on the process of domestication, the conditions of animal husbandry, and the advances in agriculture. Such studies demand the cooperation of both zoologists and paleobotanists. In addition, microscopic analysis of the floors of excavated buildings may help to identify the functions of individual rooms. The emergence of Mesopotamian civilization
The Late Neolithic Period and the Chalcolithic Period. Between about 10,000 bce and the genesis of large permanent settlements, the following stages of development are distinguishable, some of which run paralleclass="underline" (1) the change to sedentary life, or the transition from continual or seasonal change of abode, characteristic of hunter-gatherers and the earliest cattle breeders, to life in one place over a period of several years or even permanently, (2) the transition from experimental plant cultivation to the deliberate and calculated farming of grains and leguminous plants, (3) the erection of houses and the associated “settlement” of the gods in temples, (4) the burial of the dead in cemeteries, (5) the invention of clay vessels, made at first by hand, then turned on the wheel and fired to ever greater degrees of hardness, at the same time receiving almost invariably decoration of incised designs or painted patterns, (6) the development of specialized crafts and the distribution of labour, and (7) metal production (the first use of metal—copper—marks the transition from the Late Neolithic to the Chalcolithic Period).
These stages of development can only rarely be dated on the basis of a sequence of levels at one site alone. Instead, an important role is played by the comparison of different sites, starting with the assumption that what is simpler and technically less accomplished is older. In addition to this type of dating, which can be only relative, the radiocarbon, or carbon-14, method has proved to be an increasingly valuable tool since the 1950s. By this method the known rate of decay of the radioactive carbon isotope (carbon-14) in wood, horn, plant fibre, and bone allows the time that has elapsed since the “death” of the material under examination to be calculated. Although a plus/minus discrepancy of up to 200 years has to be allowed for, this is not such a great disadvantage in the case of material 6,000 to 10,000 years old. Even when skepticism is necessary because of the use of an inadequate sample, carbon-14 dates are still very welcome as confirmation of dates arrived at by other means. Moreover, radiocarbon ages can be converted to more precise dates through comparisons with data obtained by dendrochronology, a method of absolute age determination based on the analysis of the annual rings of trees.