Each subsample was treated with 1M HCL (80° C for 2h), 1M Na OH (80° C for 2 h) and again in acid, with rinsing in between.Two of the three samples were then bleached in Na OCL (2.5% at p H-3 for 30 min).At the same time, the British Museum was invited to help in the certification of the samples provided and in the statistical analysis of the results. The age of the shroud is obtained as AD 1260-1390, with at least 95% confidence. The three containers containing the shroud (to be referred to as sample 1) and two control samples (samples 2 and 3) were then handed to representatives of each of the three laboratories together with a sample of the third control (sample 4), which was in the form of threads.
On the basis of the stylistic details and the historical evidence the cope could be dated at ~ AD 1290 - 1310 (reign of King Phillipe IV).
Because it was not known to what degree dirt, smoke or other contaminants might affect the linen samples, all three laboratories subdivided the samples, and subjected the pieces to several different mechanical and chemical cleaning procedures.
One-third received no further treatment, one-third was submitted to a weak treatment with 0.5% HCL (room temperature), 0.25% Na OH (room temperature) and again in acid, with rinsing in between.
The final third was given a strong treatment, using the same procedure except that hot (80° C) 5% HCL and 2.5% Na OH were used.
To confirm the feasibility of dating the shroud by these methods an intercomparison, involving four AMS and two small gas-counter radiocarbon laboratories and the dating of three known-age textile samples, was coordinated by the British Museum in 1983. The strip came from a single site on the main body of the shroud away from any patches or charred areas.
The results of this intercomparison are reported and discussed by Burleigh . Three samples, each ~50 mg in weight, were prepared from this strip.
Among those present when the sample as cut from the shroud were Cardinal Anastasio Ballestrero (Archbishop of Turin), Professor L. The laboratories were not told which container held the shroud sample.
Gonella (Department of Physics, Turin Polytechnic and the Archbishop's scientific adviser), two textile experts (Professor F. Because the distinctive three-to-one herringbone twill weave of the shroud could not be matched in the controls, however, it was possible for a laboratory to identify the shroud sample.
It was first displayed at Lirey in France in the 1350s and subsequently passed into the hands of the Dukes of Savoy.