How it began
The prehistoric complex of Provadia-Solnitsata lies near the modern town of Provadia in northeastern Bulgaria, above the Mirovsko rock salt deposit. It holds the remains of the oldest salt production center in Europe, dated 5500 to 4200 BCE. Salt making began at the start of the Late Neolithic, between 5500 and 5200 BCE, in dome ovens built inside the houses of the settlement. Brine boiling in pottery there is the earliest case of this technology recorded in Europe. The people were a prehistoric culture on the territory of present-day Bulgaria.
How it works
In the first phase brine was boiled in pots inside domed ovens. From about 5200 BCE production moved outside the settlement to open-air installations. Deep, wide pits were packed with thick-walled ceramic vessels shaped like inverted cones, with mouths 30 to 70 centimeters across and walls up to 2.5 centimeters thick. Fires burned at the bottom of the pit between the touching vessels. As the brine boiled away it left hard conical bodies of salt.
What changed first
In the Middle and Late Chalcolithic, from 4700 to 4200 BCE, output reached what the excavator calls industrial quantities. A single load of one open-air installation could yield several tons of salt. The salt was meant entirely for trade and went south across the Balkan Mountains and out by way of Lake Varna. It served both as an everyday commodity and as a form of money. The settlement was enclosed by stone walls 2 to 3 meters thick, described as the earliest stone fortification in Europe.
What lasted
Vassil Nikolov, who led the excavations, argues that the wealth from specialized salt production and trade drove the development of the Provadia Lakes area and explains the gold-rich Varna necropolis of the 5th millennium BCE. He describes Solnitsata as the first prehistoric urban center in Europe, with a production zone, a citadel, a ritual pit and a necropolis spread over about 13 hectares.
Where it stands today
Archaeological research at the site began in 2005 and its first ten years of results were summarized in 2016 in the journal Mediterranee. Studies continue on the production center, the citadel and the Late Chalcolithic necropolis. The walls show repeated earthquake damage and rebuilding around 4600 and 4500 BCE.
