The tax-man cometh: Iron Age Israelite jar handle with royal seal.
They didn’t call it the “Iron Age” for nothing!
It turns out that, locked inside the ceramic fabric of bits of ancient pottery, are the fingerprints of our planet’s magnetic history. Newly detectable via scientific technology, the patterns of magnetic field fluctuation now emerging have proved more “choppy” — indeed inexplicable — than we ever imagined. It is truly one of the least understood of all geo-physical processes.
The magnetic minerals present in the potters’ clay were frozen in time at the moment when each piece was crafted and fired, creating a unique record. The same phenomenon is present in rocks, of course, at the time of their formation, but those datum points are measured in eons. With ancient pottery, however, the relatively rapid evolution of styles, plus the impressed seals of a progression of known rulers, makes possible a rather precise timeline.
Among the authors of the just-published source article (in the journal PNAS) is Erez ben-Yosef, an Israeli archaeologist from Tel Aviv University. For the full story and all the connections, see this piece published today on the NPR web-site:
http://www.npr.org/sections/thetwo-way/2017/02/14/515032512/iron-age-potters-carefully-recorded-earths-magnetic-field-by-accident
Tom Powers -- VIEW FROM JERUSALEM 
Interesting. I also read that a 2,000 year old jar of skin cream was unearthed in London–still bearing the fingerprint of its last user. Jim