Eleven stone masks that are the oldest yet discovered in the world are now on display in Jerusalem after experts worked for a decade to determine their age and origin.

Determined to be around 9,000 years old, the masks were reportedly found in the Judean desert and the hills near Jerusalem, according to The Associated Press. Researchers believe they were used in ancient communal rituals. 

"It's quite exciting," James Snyder, director of the Israel Museum, where the masks will be on display for seven months, told the AP. "When you go back to objects that are this old, that are so much before the theology that becomes Judaism, Christianity and then Islam, to feel that there is a kind of a connection, that this is all part of a continuous story, is something that is pretty thrilling."

The stone masks are believed to have been created in the Holy Land around the time of the agricultural revolution, when people left hunter-gatherer survival to become farmers, exhibit curator Debby Hershman told the AP.

"It's the most important revolution that ever happened," Hershman said, adding that the people who made the masks "are actually the founders of civilization."

Probably intended to look like skulls, the artifacts feature a wide range of expressions. Experts have been working for about 10 years to figure out where they came from. During the past several decades, individuals collected most of the masks, which have since undergone carbon-14 testing to determine their authenticity.

The Israel Museum hosting the exhibit actually only owns two of the masks, one of which was found in an Israeli excavation, while the other came from the collection of general and politician Moshe Dayan, who died in 1981.

Hershman found photographs of similar Neolithic masks and tracked down New York collectors Judy and Michael Steinhardt, who agreed to loan their collection.

"The masks represent a near eternal visage, their stone substance both powerful and quiet," Judy Steinhardt said in the exhibition catalog, as quoted by the AP. "Michael and I have lived with these masks for the past 25 years and we love spending quiet hours in our library together surrounded by these evocative works."

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