Secondly, looting has been a fact of life for archaeological sites, dating at least back to Roman times.

The provenance of a looted object is difficult or impossible to determine.

An inscription from the tenth year of Assyrian king Ashur-Dan III refers to an eclipse of the sun, and astronomical calculations among the range of possible dates identify the eclipse as having occurred 15 June 763 BCE.

The date can be corroborated with other mentions of astronomical events and a secure absolute chronology established, that ties the relative chronologies into our calendar.

In the series, the conjunction of the rise of Venus with the new moon provides a fixed point, or rather three fixed points, for the conjunction is a periodic occurrence.

Astronomical calculation can therefore fix, for example, the first dates of the reign of Hammurabi in this manner either as 1848, 1792, or 1736 BC, depending on whether the "high" (or "long"), "middle" or "low (or short) chronology" is followed.

Worse yet, many archaeological finds have not yet been published, much less translated. Many of our important source documents, such as the Assyrian King List, are the products of government and religious establishments.

They often have a built-in slant in favor of the king or god in charge.

The major schools of thought on the length of the Dark Age are separated by 56 or 64 years.

This is because the key source for their dates is the Venus tablet of Ammisaduqa and the visibility of Venus has a 56/64) There have been other attempts to anchor the chronology using records of eclipses and other methods, but they are not yet widely supported.

Thus by piecing together many records a relative chronology is arrived at, relating dates in cities over a wide area.

For the first millennium BC, the relative chronology can be tied to actual calendar years by identifying significant astronomical events.

The tablets or inscriptions in question still have value, though one does have to keep the slant in mind.