A richly decorated object called the Stanard of Ur was found in the royal cemetery at Ur, an important city in southern Mesopotamia. It dates to about 2500 BC. Its two main panels depict scenes of peace (shown) and war in mosaic inlays of lapis lazuli, shell, colored stone, and mother-of-pearl.
Few interpretations of archaeological remains endure unchallenged. New data and new understandings of the way that societies operate lead scholars constantly to revise and refine their explanations of the past. Mesopotamia's archaeology is no exception: There are lively debates on topics such as the origins of agriculture, the beginning of writing, and the development of civilization, in which Mesopotamia features prominently, and other more local subjects from the prehistoric period, such as the significance of the Uruk phenomenon and the origin of the Sumerians, are also of absorbing interest to archaeologists.
In the historical period, one of the major problems is with chronology, although the sequence of development is generally well established, there are major areas of uncertainty. For the later third and second millennia, there is a difference of more than a century between the High and Low Chronologies: Each can be supported by pieces of convincing evidence, but only one can be correct.
The fabric of Mesopotamian chronology is draped like a curtain from a few secure hooks, and like curtain hooks, some of these are moveable. Between them there are lengths of solid fabric whose substance remains the same wherever they move along the rail, but the material between them is less solid and can be stretched or contracted. As a result, for example, the length of the period between the fall of the Akkadian dynasty and the accession of Ur- Nammu, the first king of the Ur III dynasty, is uncertain, although the duration of these dynasties themselves is well known. One hundred and sixty-seven and a half years, as the Sumerian King List says? Sixty-six years, a revised version based on the probability that some of the intervening dynasties were contemporary? Thirty years, the duration of the longest-lasting of these dynasties, that of Uruk? None, and in fact a small overlap, with the shadowy latest kings of Akkad contemporary with the early years of Ur-Nammu?
A huge volume of written data, such as royal inscriptions, official documents, letters, omen texts, and chronicles, provide the raw material from which the historical framework has been constructed. Well-documented periods, often those that had strong rulers and were politically stable, form the strong fabric of the curtain; anarchical or poorly documented periods are the gauzy patches between. Independently datable events that were recorded are the hooks on which the fabric hangs: the eclipse that occurred on June 15, 763 B. C. E., provides a secure hook on which to hang the strong fabric of first-millennium chronology, although even here there are gauzy patches, such as the ill-documented years 630-627 B. C. E., when it is unclear whether Ashurbanipal was still alive. In contrast, in the second millennium the moveable hook provided by the observations of Venus in the reign of Ammi-saduqa places that king's accession in three or even four possible places: 1702, 1646, 1582, or perhaps 1550 B. C. E.
Most scholars opt to use the Middle Chronology (dating Ammi-saduqa's accession at 1646 B. C. E.), not because it is most convincing but because it is a convenient temporary fixed point until the correct date is finally established: Scholarly consensus on the historical framework greatly facilitates discussion of other issues. Work to establish a firm chronology, however, continues, each little piece of evidence that can be discovered or deduced making the picture a little clearer.