AS HIS TEAM UNEARTHED a cache of 73 stone steles buried in a mound in southwestern Iran, archaeologist Abbas Moghaddam of the Iranian Center for Archaeological Research added yet one more question to his growing list about the people who lived at the ancient settlement of Chega Sofla some 6,000 years ago. Since he started leading excavations in 2016 at this site amid the rich agricultural fields of the Zohreh Valley, 10 miles north of the Persian Gulf, Moghaddam and his team have found surprise after surprise that have both deepened and complicated their understanding of the farmers who lived there during the Later Village Period (ca. 5000-3700 B.c.). The cache of steles, some of which were carved with depictions of ibexes confronting each other, was found beneath the floor of the village's temple. This is the first temple that dates to this period-also known as the Chalcolithic, or Copper Age-to have been excavated in Iran.

During this era, just before the rise of the earliest cities in Mesopotamia and Iran around 3500 B.C., people lived in increasingly complex alliances of villages. Moghaddam's excavations at Chega Sofla have yielded an unprecedented wealth of detail about this pivotal moment. The inhabitants appear to have been the first in the world to use fired bricks and to bury their dead with silver ornaments. They were also among the earliest to adopt a standardized system of weights that could be used to conduct trade across a wide region. "We are opening eyes to just how sophisticated the people of the Zohreh Valley were," says Moghaddam. "No one expected this. It's like the Metropolitan Museum of Art for the Chalcolithic."