Israel acknowledged on Friday that an inscription in clay found in the country's south bearing the name of Darius the Great, ruler of the ancient Persian Empire, was not authentic.

The shard of pottery in question was discovered by a passerby last December and caused a sensation as the first mention of sixth century B.C. empire builder to appear in Israel.

After the news broke earlier this week, an expert in ancient Aramaic inscriptions approached the Israel Antiquities Authority to explain that she herself had actually etched those words onto the ancient fragment.

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The unnamed expert, part of a foreign expedition last summer to the Tel Lachish archaeological site, told officials that she had scratched the words into pottery as a demonstration while explaining to students how artifacts were historically inscribed.

She said that she then left the altered piece at the site where a Canaanite city once stood, about 40 kilometers southwest of Jerusalem, the Antiquities Authority said.

Authorities said they determined the misidentification of the artifact had come about "unintentionally and without malice" but described the expert's decision to leave behind the newly inscribed shard as "careless." The piece of pottery was examined in labs and found to be ancient, creating confusion.

Gideon Avni, the chief scientist of the Antiquities Authority, said it "takes full responsibility for the unfortunate event."

"In terms of ethical and scientific practices, we see this as a very severe occurrence," he said, noting that such cases remain extremely rare.

The authority said it will conduct a review of all procedures and policies at foreign expeditions nationwide. It was not immediately clear if any action would be taken against the unnamed expert behind the inscription.