Civilization began 5,500 years ago in the lush valley between the Tigris and Euphrates rivers in Mesopotamia, now called Iraq. We know because we learned it in high school.
Apparently we learned wrong, according to archaeologists from the University of Chicago's Oriental Institute.
McGuire Gibson and his colleagues at the institute have unearthed the remains of a 5,500-year-old Syrian city that is at least as old as the better-known cities 400 miles southeast in Iraq.
The discovery of the as-yet-unnamed city suggests that the human urge to live together, pool resources and cooperate for the greater good arose substantially earlier than is now believed, and perhaps in more than one place.
"We have to rethink how we see civilization developing," Gibson said. The new discovery and others nearby "mean that the development of kingdoms or early states occurred before writing was invented and before the appearance of several other criteria we think of as marking civilization."
Among the artifacts that mark the site as an early city are what appear to be massive city walls, a commercial-scale bakery, what might be the oldest known brewery and an assortment of seals.
These seals, which range from simple stones with incised markings to ornate, beautifully carved figurines, were used for making impressions in clay to seal and identify food and trade goods. They suggest a hierarchy of authority with several layers of bureaucracy - a sure sign of civilization.
"This is really exciting," said archeologist Gil J. Stein of Northwestern University. "It fits in nicely with the picture that has been emerging at other sites" - such as nearby Tell Brak - that sophisticated cities arose earlier than had been believed.
The first permanent settlements in the Middle East developed much earlier, perhaps about 9000 B.C., according to Sema'am I. Salem of California State University, Long Beach. That was 2,500 years before the first settlements in China and 6,000 years before the first in Western Europe.
But these settlements lacked the characteristics we have come to associate with cities and civilization - such as city walls, communal food production, breweries and bureaucracy.
According to Salem, the transition from a hunter-gatherer population to a more settled one was triggered by climate changes associated with the end of the last ice age about 10,000 B.C. As Middle Eastern deserts spread northward, he said, hunter-gatherers were forced to settle in areas with reliable water sources.
Those settlements led to the cultivation of plants and the domestication of animals, but it was a millennium or more before they turned into cities.
The newly discovered city was found at a massive mound called Tell Hamoukar, about five miles from the Iraqi border. A small village of mud brick houses sits on the southern and eastern slopes, a modern cemetery marks the crest, and the surface is littered with shards of ancient pottery exposed by rain and snowmelt.
Unlike the cities of Ur and Uruk in Mesopotamia, Tell Hamoukar is not on the banks of a river. It does, however, lie along a trade route that connected the ancient cities of Aleppo and Nineveh. That location, and the fact that the area produced abundant grain and grass for animal fodder, could have contributed to its growth.
Gibson's team was planning to excavate at several other sites in Syria that were in danger because of development or illegal digging. But a visit to Tell Hamoukar in April 1999 with officials from the Syrian Directorate General of Antiquities convinced them that it was in even greater danger because of the village and erosion.
They came back in August, mapped the site and dug trenches down three of the mound's muddy slopes, where children had been sliding on sheets of cardboard and metal and on serving trays. They found more than they bargained for, Gibson said.
"This site will add tremendously to what we know about the beginnings of civilization," he said.
The lower levels of the excavation reveal the presence of a "surprisingly large" settlement dating to at least 4000 B.C., he said. That habitation spread out over 500 acres, which would make it comparable in size to some of the Middle East's largest ancient cities.
Gibson speculates that the entire 500 acres was not inhabited at any one time, however. "Most probably, in this early phase, there was a village or a couple of villages that shifted location within that acreage," he said.
"We're not calling [the earlier habitation] a city, because we haven't trenched yet, but we could have a very large settlement from a much earlier time."
Beginning about 3700 B.C., Tell Hamoukar was a well-organized, prosperous town of about 30 acres enclosed by a defensive wall that was 10 feet tall and 13 feet wide. Archeologists will be digging at the site for years, but what they have already found is intriguing.
Several of the mud brick buildings contain large dome-shaped ovens, also made of mud brick and fired through regular use. Each oven is large enough to bake bread for hundreds of people.
Other ovens were used for cooking meat and other foods and for charring grains for a brewery. Large vats found nearby contained the remains of barley.
"They were almost certainly a beer-drinking people," Gibson said.
There is also evidence of widespread pottery manufacture. "The ability of the local potters was extraordinary," he said. "Some of the fine wares are as thin as the shell of an ostrich egg."
The final key to recognizing the Tell Hamoukar site as a city was the discovery of the seals.
One particularly fine piece is in the form of a leopard with 13 spots represented by dowels inset in holes in the figurine. Others are in the shapes of deer, bears and ducks.
"We would propose that the larger, more elaborate seals with figurative scenes on the stamping surface were held only by the few people who had greater authority, while the smaller, simply incised seals were used by many more people with less authority," Gibson said.
The city, whose name has not been discovered, did not survive long. Beginning about 3400 B.C., pottery and other materials from Uruk become much more common.
"It's as if a whole new city was being formed," Gibson said, speculating that the region was conquered by the Mesopotamians. Archaeologists have previously found evidence of Uruk-like cities from this period throughout Syria, Iran and Saudi Arabia, suggesting an aggressive period of colonization or conquest.
And then, a few hundred years later, the Uruk-like city at Tell Hamoukar "came to a very sudden end."
"It was gone and replaced by something very different, something local again," Gibson said. He hopes further excavations will shed light on how and why the Mesopotamian empire collapsed.