The results of this intercomparison are reported and discussed by Burleigh . Three samples, each ~50 mg in weight, were prepared from this strip.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.The procedures for taking the samples and treating the results were discussed by representatives of the three chosen laboratories at a meeting at the British Museum in January 1988 and their recommendations = standard deviation) errors, of the Shroud of Turin and control samples, as supplied by the three laboratories (A, Arizona; O, Oxford; Z, Zurich) (See also Table 2.) The shroud is sample 1, and the three controls are samples 2-4. The sampling of the shroud took place in the Sacristy at Turin Cathedral on the morning of 21 April 1988. All these operations, except for the wrapping of the samples in foil and their placing in containers, were fully documented by video film and photography.The second pair of subsamples was treated with a commercial detergent (1.5% SDS), distilled water, 0.1% HCL and another detergent (1.5% triton X-100); they were then submitted to a Soxhlet extraction with ethanol for 60 min and washed with distilled water at 70° C in an ultrasonic bath (method b).The Oxford group divided the precleaned sample into three.All laboratories examined the textile samples microscopically to identify and remove any foreign material.The Oxford group cleaned the samples using a vacuum pipette, followed by cleaning in petroleum ether (40° C for 1 h) to remove lipids and candlewax, for example.Zurich precleaned the sample in an ultrasonic bath.After these initial cleaning procedures, each laboratory split the samples for further treatment.Testore of Department of Materials Science, Turin Polytechnic and G. If the samples had been unravelled or shredded rather than being given to the laboratories as whole pieces of cloth, then it would have been much more difficult, but not impossible, to distinguish the shroud sample from the controls.Vial of Musée des Tissues and Centre International d'Étude des Textiles Anciens in Lyon), Dr M. Tite of the British Museum, representatives of the three radiocarbon-dating laboratories (Professor P. (With unravelled or shredded samples, pretreatment cleaning would have been more difficult and wasteful.) Because the shroud had been exposed to a wide range of potential sources of contamination and because of the uniqueness of the samples available, it was decided to abandon blind-test procedures in the interests of effective sample pretreatment.