When ISIS fighters detonated explosives inside the gate of the Temple of Nabu at Nimrud earlier this month, they destroyed more than a reconstructed ancient temple. They attacked one of the Assyrian empire's greatest centers of learning. The temple was originally constructed by the Assyrian king Ashurnasirpal II (ruled from 883--859 BC) to stand alongside the new palace he had built for himself on top of the citadel at Nimrud (this palace was also destroyed by ISIS last year). The patron god of writing and scribes, Nabu was originally worshipped in the southern Mesopotamian city of Borsippa where he was venerated as the son of the chief Babylonian god Marduk. Ashurnasirpal acknowledged the cultural debt by naming the new temple Ezida, meaning 'the true house', the same name given to the temple of Nabu in Borsippa. Little remains of Ashurnasirpal's temple, for the later king Adad-Nirari III (ruled 811--783 BC) carried out a massive project to rebuild the temple in 798 BC. The new temple featured two equal-sized sanctuaries for Nabu and his divine consort Tashmetum. The main entrance, known as the Fish Gate, was flanked by two gold-plated statues of mermen who represented the mythical Seven Sages who had brought knowledge to the earth in primeval times. Inside the gates the temple of Nabu functioned as a centre of learning and scholarship, as evidenced by a library, which British excavators uncovered there in the 1950s. The names appended to documents in the archives reveal that families of scholars worked at the temple for generations, passing their profession from father to son.

What forms did their scholarship take? Out of around 300 tablets found in the library 30 per cent concerned the interpretation of omens. Lunar and solar eclipses as well as astronomical observations of the stars, moon, and Venus were all thought to contain messages from the gods. Other texts explain the meanings of deformed births, or the patterns made by crawling ants or flocks of birds. Still others contained illustrated instructions for how to read the livers of slaughtered animals. Scholars from the temple routinely wrote to the royal court to keep the king informed of the latest omens. Another 30 per cent were incantation texts, usually related to medical issues. It was hoped that ritual repetition of the formulas could cure various conditions such as epilepsy, toothaches, and baldness. Possibly more useful was a catalogue of medicinal plants also found in the library. The rest of the tablets include a list of proverbs, prayers to various gods, and inscriptions prepared by the scribes to record the official histories of the Assyrian kings.

Possibly the most fascinating documents from the temple archive are several tablets featuring charts which show cuneiform signs from the scribe's own time alongside attempts to reconstruct the earliest cuneiform signs used two thousand years earlier. The signs do not closely resemble what we know of the earliest cuneiform, but it was an admirable effort and one that showed a serious attempt by the scribes to understand their own past.

Day-to-day life in the temple often featured mundane tasks and petty bureaucratic disputes. One letter speaks of the growth of fungus in the inner courtyard and in some of the storehouses and attempts by the priests to remove it. Another letter to the king complained that a priest named Pulu was making unauthorised changes to the temple furnishings and modifying some of the rituals. 'No one can do [anything]; there is an order to remain silent', wrote the traditionally-minded complainant, adding 'But they have changed the old rites!' Another letter, possibly from the same author, found fault with an upcoming ceremony involving a visit to the temple by a statue of the goddess Ishtar because 'it is not ancient -- your father introduced it.'

The tablets from the Nabu Temple archive are now housed in the British Museum in London and the Iraq Museum in Baghdad. The mermen which once guarded the entrance to the temple were still standing there, albeit broken and missing their gold plating, when ISIS blew up the Fish Gate. Video footage shows broken pieces of the statues lying amongst the rubble. The symbolic significance of destroying the entrance to what was once a center of ancient learning is obvious.