Radiocarbon dating measures the proportion of the radioactive carbon 14 isotope remaining in an organic sample, wood, bone, textile fiber, charcoal or parchment, and converts that proportion into an age using the isotope's known and constant rate of radioactive decay. The American chemist Willard Libby developed the method at the University of Chicago and published it in 1949, providing archaeology for the first time with an absolute dating technique that did not depend on comparison with other dated material or on written records, a contribution recognized with the 1960 Nobel Prize in Chemistry. Later refinements, calibration curves that correct for past fluctuation in atmospheric carbon 14 and accelerator mass spectrometry that allows a usable result from a milligram sized sample, have since made the method both more accurate and far less destructive to apply to a precious object.
Claimed relics and sacred manuscripts are among the most consequential objects radiocarbon dating has been applied to, since the method can directly test a devotional or institutional claim about an object's age against physical measurement, independent of tradition, provenance record or stylistic judgment. Radiocarbon results have both confirmed and, in well publicized cases, contradicted a claimed relic's traditional dating, and the atlas records radiocarbon findings as physical evidence to be weighed alongside, not automatically overriding, an object's documented custodial history.