The Prism of Sennacherib.

This hexagonal clay prism (often called the Taylor prism) records the deeds of the Assyrian king, Sennacherib, c. 689 BCE. Sennacherib was an important figure in the Old Testament and is mentioned in II Kings. (I saw this piece when I was at the University of Chicago’s Oriental Institute on Saturday but wasn’t able to get a good photo. Fortunately you can find just about anything on the internet.) Here’s the commentary from the Oriental Institute:

On the six inscribed sides of this clay prism, King Sennacherib
recorded eight military campaigns undertaken against various peoples
who refused to submit to Assyrian domination. In all instances, he
claims to have been victorious. As part of the third campaign, he
beseiged Jerusalem and imposed heavy tribute on Hezekiah, King of
Judah-a story also related in the Bible, where Sennacherib is said to
have been defeated by "the angel of the Lord," who slew 185,000
Assyrian soldiers (II Kings 18-19).

There is a complete translation of all six columns at the Sennacherib Prism site where I found the photo. And here is Byron’s poem, "The Destruction of Sennacherib," to complement it:

The Assyrian came down like the wolf on the fold,
And his cohorts were gleaming in purple and gold;
And the sheen of their spears was like stars on the sea
When the blue wave rolls nightly on deep Galilee.

Like the leaves of the forest when Summer is green,
That host with their banners at sunset were seen:
Like the leaves of the forest when Autumn hath blown,
That host on the morrow lay withered and strown.

For the Angel of Death spread his wings on the blast,
And breathed in the face of the foe as he passed;
And the eyes of the sleepers waxed deadly and chill,
And their hearts but once heaved, and for ever grew still.

And there lay the steed with his nostril all wide,
But through it there rolled not the breath of his pride:
And the foam of his gasping lay white on the turf,
And cold as the spray of the rock-beating surf.

And there lay the rider distorted and pale,
With the dew on his brow and the rust on his mail;
And the tents were all silent, the banners alone,
The lances unlifted, the trumpets unblown.

And the widows of Ashur are loud in their wail,
And the idols are broke in the temple of Baal;
And the might of the Gentile, unsmote by the sword,
Hath melted like snow in the glance of the Lord!

– George Gordon Lord Byron (1788-1824)

It is unclear what actually caused Sennacherib to lift the siege of Jerusalem, but illness within the camp may have had at least something to do with his decision. Besieging armies throughout history have been beset by disease as a result of poor sanitary conditions and close quarters.