The measurements were carried out independently in three accelerator mass spectrometry (AMS) laboratories located at the University of Arizona, Tucson, Arizona, USA, Oxford University, Oxford, England, and ETH-Hönggerberg, Zürich, Switzerland with assistance for certification and data analysis provided by the British Museum.
The author concludes that, although the procedures followed differed substantially from those recommended at a workshop organized by the Pontifical Academy of Sciences, the results are credible.
AD 1260-1390" was the result of a computer hacking, allegedly by Arizona radiocarbon dating laboratory physicist Timothy W.
At one end of the room had been set a low platform which three men mounted ... Dr Michael Tite, with the Oxford radiocarbon-dating laboratory's Professor Edward Hall and Hall's chief technician, Dr Robert Hedges. their only `prop' was a blackboard behind them on which someone had rather crudely scrawled: `1260-1390! as Dr Tite explained, these numbers represented radiocarbon dating's calculation, to a ninety-five per cent degree of probability, of the upper and lower dates of when the Shroud's flax had been harvested.
Representing an average of the laboratories' findings, which had proved in excellent agreement with each other, they indicated that the Shroud's raw flax had most likely been made into linen on or about the year AD 1325, give or take sixty-five years either way.""That the shroud's cloth dated not to the first century but to the Middle Ages was reported on October 13, 1988, after samples were carbon-dated.
I will link the headings back to my previous, "My theory ..." posts on those topics.
It is my emphasis below unless otherwise indicated.