TEL AVIV – Archaeologists in Iraq made a surprising discovery when they unearthed a seventh century BC palace in the ruins of the biblical prophet Jonah’s tomb, a site destroyed by the Islamic State in 2014.

The palace, built by the biblical Assyrian King Sennacherib and renovated by his son Esarhaddon, was discovered under the Nabi Younus shrine in Mosul near the ancient city of Nineveh.

After IS infiltrated the city in 2014, the terror group blew up the shrine. Iraqi troops managed to liberate the site in January of this year.

Eleanor Robson, head of the British Institute for the Study of Iraq, told Britain’s Daily Telegraph that the terror group’s destruction had opened the way to a “fantastic find.”

“The objects don’t match descriptions of what we thought was down there,” she said. “There’s a huge amount of history down there, not just ornamental stones. It is an opportunity to finally map the treasure-house of the world’s first great empire, from the period of its greatest success.”

“(It is) far more damaged than we expected,” Culture Minister Salim Khalaf said.

The terror group had also dug tunnels beneath the demolished shrine in search of artifacts, the report said.

Iraqi archaeologist Layla Salih told the Telegraph that in the tunnels she discovered a “marble cuneiform inscription of King Esarhaddon thought to date back to the Assyrian empire in 672 BCE.”

In Salih’s estimation, IS plundered hundreds of artifacts from the palace to sell on the black market.

“I can only imagine how much Daesh discovered down there before we got here,” she told the Telegraph, using the Arabic name for IS. “We believe they took many of the artifacts, such as pottery and smaller pieces, away to sell. But what they left will be studied and will add a lot to our knowledge of the period.”

Salih added that the tunnels were in danger of caving in in a matter of weeks.

IS has destroyed dozens of historical sites and tombs in the Mosul area as well as other parts of Iraq, in keeping with their belief that reverence for such relics goes against Islam.