(CNN)Sicilians may have been making wine for a lot longer than previously thought.
Researchers have found traces of 6,000-year-old wine on ancient pottery recovered in a cave in Sicily, in a discovery could rewrite the beginning of the Italian penisula's wine-making history.
Traditionally it was thought that wine production developed in the region in the Middle Bronze Age, between 1300 and 1100 BC.
The new findings, published in Microchemical Journal, would change that date by three millennia.
An international team of scholars led by Davide Tanasi of the University of South Florida (USF) ran chemical analysis on residue on a storage jar dating from the Copper Age. The pottery was recovered in Agrigento, off Sicily's southwest coast.
The results showed traces of tartaric acid and its sodium salt, which occur in grapes and the wine-making process, meaning that the region's wine production possibly began in the early fourth millennium BC.
Tanasi told CNN that the wine may have been left as an offering to underground deities.
"The cave site of Monte Kronio is also a cult place used for religious practices from prehistory to Classical times," Tanasi said. "This discovery has important archaeological and historical implications."
The researchers' next move is to work out whether the wine was red or white, according to a USF statement.
Tanasi told CNN that a different sample would have to be used and that the work would be part of a more general project on diets in prehistoric Sicily and Malta.
Experts from the USF, University of Catania, Institute of Chemical Methodologies (CNR) and Superintendence of Agrigento were involved in the discovery.