A handful of tree ring samples stored in an old cigar box have shed unexpected light on the ancient world, thanks to research by archaeologist Sturt Manning and collaborators at Cornell, Arizona, Chicago, Oxford and Vienna, forthcoming in the June issue of the Journal of Archaeological Science. The samples were taken from an Egyptian coffin; Manning also examined wood from funeral boats buried near the pyramid of Sesostris III. He used a technique called “dendro radiocarbon wiggle matching,” which calibrates radiocarbon isotopes found in the sample tree rings with patterns known from other places in the world that have already...