Hajji Firuz Tepe rises as an oval settlement mound in the Gadar River valley of West Azarbaijan Province, northwestern Iran. The mound measures roughly 200 meters across at its base and stands 10.3 meters above the surrounding plain, though archaeological deposits continue to an unknown depth below the modern surface. Sir Aurel Stein first noted the site in 1936, collecting pottery sherds from its surface. Systematic excavation came later, between 1958 and 1968, as part of the broader Hasanlu Project run by the University of Pennsylvania Museum. Archaeologists Charles Burney, T. Cuyler Young Jr., Robert H. Dyson, and Mary M. Voigt supervised four digging seasons, opening excavation squares in four different parts of the mound. The largest exposure was reached on the northeastern slope, revealing layer after layer of Neolithic habitation dating roughly from 6000 to 5400 BC.

The evidence for winemaking came from six jars, each holding about nine liters, embedded in the floor of what archaeologists believe was a kitchen in a mudbrick building occupied between 5400 and 5000 BC. Chemical analysis of the yellowish deposits inside revealed tartaric acid and calcium tartrate -- compounds strongly associated with grapes, which are one of the few natural sources of tartaric acid. More intriguing was the presence of terebinth tree resin in the same containers. Terebinth grew wild in the Gadar valley, and resin has a long history as a sealant and preservative. The Greek wine Retsina, still produced today, uses pine resin in a similar fashion. The total volume stored across the six jars amounted to 54 liters -- a quantity suggesting production beyond mere household sustenance. Clay stoppers matching the jar openings were found nearby, indicating deliberate efforts at preservation and protection from air exposure.

The Zagros Mountains separate modern Iran from Armenia, Iraq, and Turkey, and the range is home to many wild grapevine species in the Vitis family. The Gadar River valley falls within the natural distribution zone of wild grape, Vitis vinifera subspecies sylvestris. Wild vines have separate male and female plants, but pollination and grape production would have occurred readily, giving Neolithic inhabitants easy access to the fruit. Whether the first fermentation was accidental -- grapes crushed and left in a sealed jar at room temperature -- or the product of deliberate experimentation, the conditions at Hajji Firuz Tepe were ideal. The climate, the native vines, the tradition of clay vessel production, and the practice of embedding storage jars in cool earthen floors all converged to create the right environment for winemaking to emerge.

Hajji Firuz Tepe was not the end of the story. South of the site lies Godin Tepe, inhabited around 3500 to 3000 BC, where archaeologists found even larger wine jars -- 30 and 60 liters -- along with basins containing wine residue that may have served as early treading vats. Residue found on the sides of those containers, rather than the bottoms, suggests they were stored on their sides for long-term aging. The Zagros Mountains, it turns out, were a cradle of viticulture. The Neolithic occupation at Hajji Firuz Tepe has been divided into twelve phases, labeled A through L from latest to earliest, and the cultural tradition that followed -- the Dalma tradition, dating to about 5000 to 4500 BC -- appears to have grown directly from this foundation. The site stands as evidence that humanity's relationship with wine is not merely ancient but foundational, woven into the earliest experiments with agriculture and settled life.