Carbor 14 dating
The Zurich group first split each ultrasonically cleaned sample in half, with the treatment of the second set of samples being deferred until the radiocarbon measurements on the first set had been completed.The first set of samples was further subdivided into three portions.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.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).
The size of the sample then required, however, was ~500cm, which would clearly have resulted in an unacceptable amount of damage, and it was not until the development in the 1970s of small gas-counters and accelerator-mass-spectrometry techniques (AMS), requiring samples of only a few square centimetres, that radiocarbon dating of the shroud became a real possibility. The shroud was separated from the backing cloth along its bottom left-hand edge and a strip (~10 mm x 70 mm) was cut from just above the place where a sample was previously removed in 1973 for examination.It was first displayed at Lirey in France in the 1350s and subsequently passed into the hands of the Dukes of Savoy.After many journeys the shroud was finally brought to Turin in 1578 where, in 1694, it was placed in the royal chapel of Turin Cathedral in a specially designed shrine.But the three laboratories undertook not to compare results until after they had been transmitted to the British Museum.
Also, at two laboratories (Oxford and Zurich), after combustion to gas, the samples were recoded so that the staff making the measurements did not know the identity of the samples. On the basis of the Islamic embroidered pattern and Christian ink inscription, this linen could be dated to the eleventh to twelfth centuries AD. Linen from the collection of the Department of Egyptian Antiquities at the British Museum, associated with an early second century AD mummy of Cleopatra from Thebes (EA6707).
The results provide conclusive evidence that the linen of the Shroud of Turin is mediaeval.