In one of the previous lessons, we recalled that we may single out three main phases in the development through the years of archaeology as an historical discipline of humanities during the 19th, and most recently, the 20th century. We called them respectively pioneer, historical, and global archaeology. For what concerns methods one of the most important conquests of historical archaeology is what we may define the invention of stratigraphic archaeology. The first theoretical elaboration and practical experimentations of this method date from the 30s and 40s of the 20th century. On the other hand, its success and diffusion took place during the 50s and 60s of the same century. Two great British scholars are the authors of this discovery. Sir Mortimer Wheeler, one of the protagonists of the archaeology of India and one of the discoverers of the early urban culture in the Indus Valley. On the other hand Dame Kathleen Kenyon is one of the most important scholars of the archaeology of Palestine who became famous for her excavations in particular at Samaria, Jericho, and Jerusalem. This stratigraphic method in field archaeology, which faced some improvement and deepening in the years since the first intuitions by Wheeler and Kenyon, is the method universally applied today in all modern excavations, although with some variant, in any scientific excavation in any country of the world. The main characteristic of the stratigraphic method is that it put at the center of the attention the excavation of the archaeological deposit, namely the earth, which must be excavated and removed in order to recover any kind of artifacts that the soil conceals and hides. Paradoxically, modern scientific excavations does not give the maximum attention to what is discovered but to the way in which it is discovered. So archaeology passes from what is the excavation to how it is excavated. From the considerations we made in the previous lessons therefore, it seems clear that in a modern stratigraphical excavation the greatest attention is turned to the archaeological deposit, namely the earth: the true protagonist of scientific archaeology, even more than the recovered artifact itself. It is not by chance that the first handbook of stratigraphic archaeology, written by Sir Mortimer Wheeler, was called Archaeology from the Earth. The aim of stratigraphic method is to recover the largest possible amount of information from the archaeological context, keeping in mind, as already maintained, that precisely the archaeological deposit is fatally and irreparably lost during the excavation. The modern scientific excavations carried out according to the stratigraphic method, whichever variant of practical procedure is applied, is, in general terms, based on the principle that observation, registration, and interpretation of the earth of the archeological deposit are necessary. The observation of the earth, of the archeological deposit during the excavation should keep accurately into account the color, structure, and placement of the soils one meets when excavating. Moreover, only an excavation conducted following a stratigraphical method, guarantees the conditions for a correct interpretation of the excavation results. Even in the centers of great historical importance, in quite a number of excavations carried out before the discovery of the stratigraphic method, clamorous mistakes were made in the dating, precisely because the archeological deposit was not given attention and it was simply removed. In order to better understand this problem we may make two classical examples, well known to Wheeler and Keyon thanks to their experience in Oriental Archaeology. These examples concern, on the one hand, the excavation of a modest quarter of house with mudbricks structured on stone foundations, destroyed by fire, and on the other hand, the excavation of a monumental area, abandoned, and later on transformed in a waste place, for a poorer settlement not far away. In the first case, it is quite likely that inside the houses rooms, one finds, from top to bottom, a thick layer of earth, relatively packed with fragments of collapsed bricks, more or less damaged, or quite poor of ceramic fragments, and, down lower,and on the floor, quite a thin grayish layer of soil, packed with ash and burnt wood, usually quite rich in pottery. Usually, if one knows the pottery of this site, one will observe that, quite astonishingly, the pottery from the upper-level of collapsed mudbricks contains fragments from a phase older than the pottery of the lower-level with burnt beams. Of course, as it's quite patent, it is quite peculiar that an upper level contains pottery older than that of the lower-level, because, in general terms, in a normal stratification and so in the stratigraphic archaeology, the soil placed lower down is usually older than the soil placed above. The explanation for this apparent peculiar anomaly cannot be obtained if one doesn't observe, with care during the excavation, the structure, color and placement of the soils met, as explained earlier. In general terms, in fact, the explanation for this apparent peculiar phenomenon is the following: The pottery from the lower grayish level with ashes is the more recent one, because it belongs to the time of the destruction of the settlement or the building. The pottery from the upper-level of the fragmentary mudbricks is older, because it comes from the soil with which the mud bricks of the walls were made, which collapsed after the destruction of the rooms or the abandonment of the building, leading to the accumulation of the soil much poorer in ashes over the level of the burnt beams of the roofs. We may also say that, while the pottery from the level of ashes and burnt materials date the destruction of the building, the pottery fragments from the mudbricks of the walls may point, in general, to a phase immediately before the erection, and so the construction, of the building itself. In the second case, over a thick level of soil with fragments of collapsed bricks, which had heaped up inside the rooms of a monumental complex, there is a level of soil with a much more uniform color and texture, where the mudbrick fragments become rarer, and at last, evenly disappear. These soils from the lower and upper-levels, are quite different in structure, color, and placement, yet they both feature irregular perturbations of grayish soils with ashes, with frequent pottery fragments, and bone remains. If the excavation is carried out without following the principles of stratigraphic archeology, it is however possible to notice that the pottery from the excavated soils, even from the similar levels with regard to a horizontal plane, is peculiarly mixed up, and that it belongs to quite different periods. If, on the other hand, the excavation is carried out according to the principles of stratigraphic archeology, so following each strata accordingly, one will easily observe that, in the first place, the homogeneous and older pottery are relatively frequent in the soil of the lower-level of collapses of the walls, after the monumental complex was abandoned. In the second place, that the non-homogeneous pottery, dating from different periods, is quite rare in the homogeneous soil void of mudbricks, from the upper-level of aeolian accumulation over the abandoned ruins, dating from a time when the site was not regularly frequented. In the third place, finally, that the homogenous and later pottery is more abundant in the soils thick with ashes, located even at quite different heights, scattered in limited places of the excavations area. These three soils belong respectively to a lower one, to a short phase of abandonment of the settlement, characterized by the collapses of the structures no more in use, the upper one to a longer period of accumulation of soils brought from wind and rain, with sporadic and inhomogeneous materials, not due to a regular human frequentation, and the third one to the phase of waste pits from a probably not far away settlement, which penetrated, sometimes relatively in depth, both older levels of occupations. In one word, the events which in the pre-stratigraphic archaeology appeared as inexplicable perturbations in the accumulation of levels of soils in a settlement, in stratigraphic archaeology in the other way, one finds always an explanation, precisely because the strongest attention is given to the ways in which archaeological soils were created, and came one after the other. In very simple terms, an excavation carried out according to stratigraphic method is a scientific excavation, So not only what we excavate but how we excavate. This minimizes the possibilities of interpretation mistakes, while an excavation carried out ignoring the stratigraphic method leads to several interpretation mistakes and misunderstandings of the arcaeological context. However, it was rightly pointed out that in the different historical archeologies of the planet the classification of the chronological sequences of different kinds of artifacts of material culture were made in the phase of historical archaeology, previous to the discovery of stratigraphic method. Just to make one famous example: by the end of the 19th century, during his quite crititicizable excavations, Heinrich Schliemann defined nine successive strata, corresponding to nine towns, coming out, one after the other for more than two millennia, on the hill of Hissarlik in Western Anatolia, quite likely the famous Homer's Troy. The succession of towns, albeit with important clarifications and corrections, was confirmed by the American excavations led by Carl Blegen in the 30s of the 20th century, and by the recent German excavation by Manfred Korfmann. How could it happen that ancient methodological, quite rudimentary excavations, though neglecting the attention for the archeological deposit peculiar to the stratigraphic method, in Palestine at Megiddo, in Mesopotamia at Nineveh and Uruk, in Syria at Ugarit, for example, these excavations reached acceptable results several decades before the invention of the stratigraphic method. The explanation, in fact, for this peculiar event lies in the fact that when, during the first phase of historical archeology, they carried out excavations where the archeological deposit was not paid too attention, they often followed two criteria which allowed, although without a great precision, to avoid serious mistakes in the identification of the succession of archeological strata. The two criteria where the following: On the one hand, they usually worked over very large areas. And on the other hand, they removed the strata, characterized by architectural structures, one after the other. By this I mean that, by paying attention not to the soils of the archaeological deposits but rather to the architectural superimposition and working over large areas, even the continuous, yet episodic anomalies of the so-called stratigraphic perturbations, were statistically inclined to be cancelled, because attention was rather paid to the succession of architectural strata. In fact, in such a way, if the observation and registration of the succession of architectural strata and of the archaeological materials related with the relative soils were accurate, results were often satisfactory, because they obtained a kind of macro-stratigraphy, while they missed, of course, the micro-stratigraphy. Therefore, when the excavation attention was paid only to architectural succession of strata, and not yet to the structure, color, and placement of archeological deposits, so the earth, they were able to identify the great periods of the archeological sequences. But the definition of the phases in which those main periods were articulated was almost completely missed. And for these reasons it was maintained, on the one hand, that the great "invention" of stratigraphic archaeology had to be defined "stratigraphic archaeology on geological base", because in it the soils of the archaeological levels were dealt with like geologists studied the geological levels of the earth history. And on the other hand, that it was preceded by a "stratigraphic archaeology on architectural base", because in it, they did not pay attention to the succession of archeological deposits, but only to the succession of architectural strata. So, building instead of simple soil deposit. And in fact, in conclusion, these considerations about the progressive success of the stratigraphic method make us understand that the great phase of "historical archaeology" was called in this way because, with gradual improvements, which knew moments of major and more decisive improvements like those linked to Wheeler and Kenyon, it allowed, in many of the planet's archeologies, a sound chronological classification of all main artifacts of material culture of different civilizations taken into account. And by means of these method improvements of the archaeological discipline, which in general terms took place by the half of the 20th century, the study of the remains of the material culture of humankind's history entered the proper scientific phase. And for that reason, archaeology became a true historical discipline, capable to bring basic contribution to the historical reconstruction of the civilization of the ancient world.
