THE TURIN shroud is a linen cloth (4.42m x 1.13m) bearing an image of a man many believe is the crucified Jesus Christ. The cloth has been investigated scientifically, but the jury is still not completely convinced as to the age of the shroud. Obviously, if the cloth is significantly less than 2000 years old, it could not be the burial shroud of Christ. The results of the latest investigation of the shroud were announced on October 6th, claiming to have produced a replica using only materials and techniques that were available in the Middle Ages. This study will strengthen the case made by those who claim the shroud is a medieval forgery.

The shroud is kept in the Cathedral of St John the Baptist in Turin and bears the image of a man who appears to have been crucified. Many believe it is the cloth placed on Jesus Christ in the tomb, but sceptics argue that the shroud is a medieval forgery. The image is in sepia tones, but is much clearer as a black and white negative.

Byzantine tradition refers to a shroud bearing an image of Christ taken from Jerusalem to Turkey in the first century, then lost, rediscovered and brought to Constantinople in 944. However, the shroud lacks an unbroken record dating it back to the first century. It surfaced in the 1350s in the hands of a French knight and was eventually bequeathed to Pope John Paul II in 1983.

A fragment of the shroud was radiocarbon-dated in 1988 by three laboratories and their results are in agreement. The results claim a 95 per cent probability that the shroud dates from between 1260 and 1390, with the odds against the shroud dating from the first century described as “astronomical” by these investigators. The researchers interpreted the shroud as a medieval fake – forging religious relics during the 14th century was big business. But, the results of this radiocarbon dating have been disputed.

Contamination of samples can pose serious problems in radiocarbon dating and have caused several anomalous results.

In 1993 the suggestion was made at a shroud conference that a natural film of micro-organisms had built up on the surface of the shroud and this might have skewed the radiocarbon dating results. Subsequent microscopic examination of the shroud showed the presence of a biofilm and it was claimed that the procedures used to clean the shroud sample for the 1988 radiocarbon tests failed to remove this biofilm. However, about 60 per cent of the mass of the shroud sample would have to be biofilm to skew the results by 13 centuries! New radiocarbon tests are now to be carried out on the shroud at Oxford, but preliminary comments from that source seem to back the 1988 results.

The latest investigation of the shroud was carried out by an Italian group and funded by an Italian organisation of atheists and agnostics. Luigi Garlaschelli, a professor of organic chemistry at the University of Padua, claims to have reproduced the shroud using material and techniques available in the Middle Ages.

Garlaschelli and his team used a linen cloth woven using the same technique used to make the shroud. The team placed the sheet flat over a student volunteer who wore a mask to reproduce the face. The cloth was then rubbed with red ochre, a well-known medieval pigment. The cloth was artificially aged by heating it in an oven and washing it in water. The ageing removed the pigment from the cloth but left a half-tone image similar to that seen on the shroud.

In an interview with La Repubblica, Garlaschelli said that there is a widespread belief that the shroud “has unexplainable characteristics that cannot be reproduced by human means”. But, he went on: “The results obtained clearly indicate that this could be done with the use of inexpensive materials and with a quite simple procedure.”

The shroud is owned by the Vatican, but the Catholic Church makes no claims about the relic’s authenticity. In my opinion, religious relics are of little intrinsic value, but can cause serious complications for religion. So what if the chair on which Jesus sat, or the cup from which he drank, is discovered. His use of these objects did not transmute them into sacred objects. But the danger for religion is that some people insist on treating relics as sacred objects and start to venerate them. Surely the important thing for Christians is that they know the life story and teachings of Jesus. Relics are little more than show business.

William Reville is associate professor of biochemistry and public awareness of science officer at UCC – http://understandingscience.ucc.ie