ISIS' destruction of the biblical tomb of Jonah has revealed a once opulent palace and inscriptions detailing the life of an Assyrian King.

Seven clay tablets, found in a palace hidden under the Tomb of Jonah in the northern city of Mosul, describe the rule of a king named Esarhaddon.

The inscriptions describe Esarhaddon as 'king of the world', and claim he rebuilt the ancient cities of Babylon and Esagil during his reign.

They also lay out the man's family history, giving scientists fresh insight into the ancient royal bloodline of Assyria.

Scroll down for video

The texts appear similar to the inscription pictured, found in an ancient palace in Nineveh, Iraq. It reads: 'The palace of Ashurbanipal, great king, mighty king, king of the world, king of Assyria, son of Esarhaddon, king of Assyria, descendant of Sennacherib, king of Assyria'

The tablets were found in four tunnels dug by ISIS looters looking for Assyrian treasure beneath the Tomb of Jonah, a shrine sacred to both Christians and Muslims.

The site was blown up by the terror group during its occupation of Mosul from June 2014 until January 2017, when the city was retaken by Iraqi forces.

Archaeologists picking through ancient rubble left behind by the group found a previously undiscovered palace containing white marble murals of bulls, stone statues of demi-goddesses and seven marble inscriptions.

New translations of the cuneiform tablets, thought to date back to the Assyrian empire in 672BC, show the texts describe King Esarhaddon.

One inscription, in translation, reads: 'The palace of Esarhaddon, strong king, king of the world, king of Assyria, governor of Babylon, king of Sumer and Akkad, king of the kings of lower Egypt, upper Egypt and Kush [an ancient kingdom located south of Egypt]', according to a new report from Live Science.

Previous research has found that Kush rulers once ruled Egypt, and the Niveneh inscriptions claim Esarhaddon defeated Kush leaders and chose new rulers to govern Egypt.

A set of 2,700-year-old inscriptions have been found in an ancient palace buried under the ruins of a shrine in Iraq. The Nebi Yunus shrine - containing what Tomb of Jonah or 'Yunnus' as he is known in the Koran - was destroyed by ISIS militants in July 2014 (pictured)

Archaeologists assessing the damage caused by Islamic State militants to the tomb of the prophet of Jonah have found an undiscovered palace. Here, a member of the Iraqi army stands next to Assyrian stone sculptures of demi-goddesses, pictured spreading the 'water of life'

Seven clay tablets, found in a palace hidden under the Tomb of Jonah in the northern city of Mosul, describe the rule of an Assyrian king named Esarhaddon. The demi-goddess sculptures pictured were carved into the walls of the palace over 2,000 years ago

WHO IS PROPHET JONAH OR 'YUNIS'? ISLAMIC AND CHRISTIAN VERSIONS The Prophet Yunis is widely regarded as the Islamic version of the prophet perhaps more commonly referred to in the Bible as Jonah. Jonah was famously swallowed by a whale or a fish, depending on the literature, and his Islamic narrative has some similarities as well as substantial differences to the Hebrew Bible story. The Quran describes Jonah as a righteous preacher of the message of God but a messenger who, one day, fled from his mission because of its overwhelming difficulty. The Quran says that Jonah made it onto a ship but, because of the powerfully stormy weather, the men aboard the ship suggested casting lots to throw off the individual responsible. The Prophet Yunis is widely regarded as the Islamic version of the prophet perhaps more commonly referred to in the Bible as Jonah When the lots were cast three times and Jonah's name came out each time, he was thrown into the open ocean that night. A gigantic fish came and swallowed him, and Jonah remained in the belly of the fish repenting and glorifying God. The Christian version of the story goes that a huge storm arises and the sailors, realising it is no ordinary storm, discover Jonah is to blame. Jonah admits this and tells them if he is thrown overboard, the storm will cease. The sailors try to dump as much cargo as possible before giving up, but feel forced to throw him overboard, at which point the sea calms. The sailors then offer sacrifices to God. Jonah is miraculously saved by being swallowed by a large fish in whose belly he spends three days and three nights. While in the great fish, Jonah prays to God in his affliction and commits to thanksgiving and to paying what he has vowed. God commands the fish to spew Jonah out. Advertisement

Another of the tablets says that Esarhaddon 'reconstructed the temple of the god Aššur [the chief god of the Assyrians],' rebuilt the ancient cities of Babylon and Esagil, and 'renewed the statues of the great gods'.

The texts say Esarhaddon is the son of Sennacherib, who reigned over Assyria from 704–681 B.C, and a descendent of Sargon II, who was also 'king of the world, king of Assyria', reigning 721–705 B.C.

The Nebi Yunus shrine - containing what Muslims and Christians believe to be the tomb of Jonah or 'Yunnus' as he is known in the Koran - was destroyed by ISIS militants in July 2014.

The inscriptions describe Esarhaddon as 'king of the world', and claim he rebuilt the ancient cities of Babylon and Esagil during his reign. This image shows another archaeological find in the ISIS tunnels, which archaeologists have been exploring since January 2017

This image shows a winged bull carved into the palace, with archaeologist Layla Salih (right), who is leading a five-person team carrying out the emergency documentation of Jonah's tomb

Weeks after overrunning Mosul and much of Iraq's Sunni Arab heartland, ISIS militants rigged the shrine and blew it up, sparking global outrage.

ISIS militants believe giving special veneration to tombs and relics is against the teachings of Islam.

Tunnels dug by the group were not professionally built, leaving them unstable and at risk of collapse, burying the ancient palace and its remaining artefacts.

The finding is the first example of ISIS militants tunnelling underneath historic sites to find artefacts to loot.

Excavations at the Tomb of Jonah had previously been carried out by the Ottoman governor of Mosul in 1852. And the Iraqi department of antiques studied the site in the 1950s. Neither dug as far as the ISIS militants. Pictured are two of the group's tunnels

The finding is the first example of ISIS militants tunnelling underneath historic sites to find artefacts to loot. This image shows archaeologist Layla Salih in one of the ISIS tunnels

It had long been rumoured that the shrine shared a site with an ancient palace.

Excavations had previously been carried out by the Ottoman governor of Mosul in 1852.

The Iraqi department of antiques also studied the site in the 1950s.

But neither excavation had dug as far as the ISIS militants, leaving the palace undiscovered for 2,600 years.

WHAT WAS THE ASSYRIAN EMPIRE? The Assyrian Empire was a complex Mesopotamian civilisation dating from 2,500 BC to around 600 BC. Mesopotamia, an area of ancient Asia, was where people first gathered in large cities, created governments, and learned to write. Alongside other Mesopotamian groups like ancient Babylon and the Sumerian cities, the Assyrian Empire was one of the earliest civilisations in history. As its height, the empire stretched from Egypt up through what is now Syria, Iraq, Lebanon and into Turkey. As its height, the Assyrian Empire (red) stretched from Egypt up through what is now Syria, Iraq, Lebanon and into Turkey Turkey's Kültepe district was home to a settlement of the Old Assyrian Empire from the 21st to 18th centuries BC. Over 1,000 cuneiform tablets were found in the area in 1925, revealing a rich and complex cultural heritage. Much of our knowledge of early human societies comes from stone tablets such as these, leading some scholars to label Mesopotamia 'the place where history began'. Advertisement

The palace was renovated and expanded by King Esarhaddon after it was built for his father Sennacherib.

It was partly destroyed during a ransacking as part of the Battle of Nineveh in 612 BC.

Only a handful of these 'cuneiform' slabs have ever been uncovered from the Esarhaddon period.

An Iraqi soldier standing in a section of excavated ISIS tunnel. It had long been rumoured that the shrine shared a site with an ancient palace. Excavations had previously been carried out by the Iraqi department of antiques in the 1950s, but they found nothing

Inscriptions found in the tunnels lay out King Esarhaddon's history, giving scientists fresh insight into the royal bloodline of Assyria. Pictured is the entrance to one of the tunnels

Archaeologists also unearthed two Assyrian empire-era winged bull sculptures within the Jihadist tunnels.

Two murals in white marble show the winged bulls with only the sides and feet showing.

In another section of ISIS tunnel the archaeologists found Assyrian stone sculptures of a demi-goddess, pictured spreading the 'water of life' to protect humans.

Some of the larger sculptures were likely left behind by ISIS because they feared the hill might collapse, experts said.

Mrs Salih, pictured here coming from the entrance of one of the ISIS tunnels, is leading a five-person team carrying out the emergency documentation of Jonah's tomb. She believes that ISIS forces looted hundreds of objects before Mosul was retaken by Iraqi forces

'I can only imagine how much Daesh discovered down there before we got here,' Mrs Salah (pictured) said. 'We believe they took many of the artefacts, such as pottery and smaller pieces, away to sell. But what they left will be studied'

Other removable artifacts, especially pottery, were certainly plundered, according to archaeologist Layla Salih, who is in charge of antiquities for the Nineveh province where the shrine stands.

'I've never seen something like this in stone at this large size,' Professor Eleanor Robson, chair of the British Institute for the Study of Iraq, told the Telegraph last February.

Professor Robson suggested they may have been used to decorate the women's quarter of the palace.

'The objects don't match descriptions of what we thought was down there, so Isil's destruction has actually led us to a fantastic find.'

This image reveals the damage caused by ISIS to the site of Jonah's tomb. As the city of Mosul was finally retaken, Iraqi forces battling Islamic State unveiled the destruction left behind by the jihadis last month in a series of devastating photographs

Weeks after overrunning Mosul and much of Iraq's Sunni Arab heartland, ISIS militants rigged the shrine, pictured here, and blew it up, sparking global outrage

'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.'

Mrs Salih, who is leading the five-person team carrying out the emergency documentation of Jonah's tomb, believes that ISIS forces looted hundreds of objects before Mosul was retaken by Iraqi forces.

'I can only imagine how much Daesh discovered down there before we got here,' she said.

'We believe they took many of the artefacts, 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.'