The new tombs were excavated in 2002, 2004, and 2006, with funding from the National Science Foundation, the National Geographic Society Committee for Research and Exploration, New York's Metropolitan Museum of Art, the Dellheim Foundation of Baltimore, and Johns Hopkins University.
(National Geographic News is a division of the National Geographic Society.)
Umm el-Marra is located in the Jabbul plain of northern Syria, just west of the Euphrates River. The area was once the center of a critical trade route, connecting the Mediterranean Sea to points as far east as Afghanistan.
Schwartz says he believes Umm el-Marra is the site of ancient Tuba, one of Syria's first cities and the capital of a small kingdom.
As urban centers began to form in Mesopotamia and what is now Syria, the newly emerging elites had to cement the legitimacy of their rule, Schwartz says.
The new finds at Umm el-Marraits centrally located "royal cemetery" is unique among cities of its eramay explain how those at the top got others to buy into the new social order.
"One of the ways they did it, it would seem, was by venerating rulers and burying them in the middle of the community. This made them constantly present," Schwartz explained.
"The living rulers could point to their ancestors and say, The same people that we are venerating as ancestors, they are my predecessors. Let it be recognized that they were illustrious rulers and my own authority is thus justified."
Schwartz believes the tombs were also meant to convey these same messages of power to competing city-states.
"The elite in the different cities were trying to impress one another," Schwartz said. "These tombs are not subterraneaneveryone can see them all the time."
We may never know the answer to perhaps the most intriguing question: Why were puppies and babies buried together with the deceased in Umm el-Marra?
There is almost no archaeological evidence to shed light on ancient Syrian society's rituals and beliefs, according to Augusta McMahon, a lecturer in Mesopotamian archaeology at England's University of Cambridge.
McMahon is skeptical of Schwartz's claims of infant sacrifice at Umm el-Marra.
"We have no other documentation that I know of," McMahon said. "There is no textual reference to this sort of behavior."
She suggests that high infant mortality rates may have led to mass burials of Umm el-Marra babies in the royal tombs.
"If there is an aspect of child sacrifice, you get to questions like: Which children were they? Were they the children of upper classes, the elite, the people in power who belong in the tomb? Or are they children of lower classes who were forced into this? You are confronted by a whole lot of uncomfortable questions which demand explanations," McMahon said.
While admitting that high infant mortality rates might explain the unusual burials in Umm el-Marra, Schwartz sticks to his hypothesis.
"There is evidence of human sacrifice in other burial contexts," he said. "The most famous is the city of Ur in southern Mesopotamia.
"We don't know for sure if these infants [in Umm el-Marra] were sacrificed. But I think it seems to be likely, because they are found in architectural features that otherwise contain the skeletons of animals that clearly were sacrificed."
Both McMahon and Schwartz agree that the newly discovered material at Umm el-Marra will allow researchers to paint a much more elaborate and colorful portrait of early urban civilization in Syria.
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