Scholarly debate and uncertainty have dogged efforts to specify precisely the years when various ancient civilizations thrived in the lands bordering the eastern Mediterranean Sea. An ongoing analysis of tree-ring evidence, described in the June 27 Nature, promises to bring unprecedented exactitude to the calendar of ancient history.
New data from this project yield an exact chronology of eastern Mediterranean cultures from 2220 B.C. to 718 B.C., a time span that encompasses the rise and fall of early urban centers in Mesopotamia and Egypt, as well as the emergence of societies in Greece and Rome.
"Tree-ring dating now offers the route to a new, absolute chronology of the Old World that is independent of existing assumptions, gaps in evidence, and debates," asserts a scientific team headed by Peter Ian Kuniholm, an archaeologist at Cornell University.
Although this line of investigation will probably generate a reliable time line for archaeological sites in the eastern Mediterranean, doubts still remain about the dating sequence currently proposed by Kuniholm's group, writes Colin Renfrew of the McDonald Institute for Archaeological Research in Cambridge, England, in an accompanying comment.
Prior attempts to devise chronologies for early civilizations in the Near East and Egypt relied largely on recovered documents, such as clay tablets, which outline regional successions of kings and other royal figures. Three different chronologies have been proposed on the basis of such information.
Kuniholm and his colleagues aimed to calibrate a sequence of radiocarbon dates using tree rings from a variety of ancient timbers, most of which came from modern-day Turkey. They identified what they called a floating chronology of 1,503 years, a slice of time from around the second millennium B.C. that could not be pinned to exact years.
The scientists then obtained 18 high-precision radiocarbon dates from a juniper log at a Turkish archaeological site. A statistical comparison of these measurements to radiocarbon measurements from Europe and North America, all of which have established calendar dates, resulted in a chronological …