From War Cry:
3291 BC - The Akkadians are decimated by a colossal shoggoth. A surviving warrior seeks to warn his nation's prior enemy, but King Hammurabi of Babylon doubts his word and is powerless when the creature attacks his own city.
The date for this event seems to be about 1140 years off, if JB is suggesting the actual Akkadian Empire was finished off by this thing, and 1541 years off if this is supposed to be the real Hammurabi. If we assume the cultural and personal names are a translation-convention to preserve the Mesopotamian "feel" of the historical flashback, and that the characters involved are from a couple of forgotten cultures of which the shoggoth left no trace for archeologists to unearth, then the captioned date could be accurate in the Dresdenverse.
Either way, this one's date in the Timeline may have to read "Ancient Mesopotamia (3291 BC?)" until we hear from Jim if it's just a flub from his misreading "3rd millennium BC" in a history book as the 3000s, not the 2000s.
The events of War Cry itself are in late January or early February, four months after Yoshimo's leg was broken in Dead Beat.