The Shroud of Turin, thought by some to be the burial cloth of Jesus Christ, has been studied numerous times. The shroud was first displayed in France in the 1350s and, after passing through many hands, it wound up in Turin, Italy in 1578.

Skeptics say that the cloth does not date from the time of Jesus and is therefore a forgery. A radiocarbon experiment in 1988, conducted by three different laboratories, concluded with “at least 95 percent confidence” that the linen dates to the period around 1260 to 1390 AD. Linen from the shroud was tested alongside three control samples. Since the degree of contamination from dirt, smoke, or other contaminants was unknown, the three laboratories subdivided the samples and subjected the pieces to several different mechanical and chemical cleaning procedures. One group cleaned the samples using a vacuum pipette, and then followed by cleaning them in petroleum ether. Another group precleaned the sample in an ultrasonic bath. The third group treated the samples with dilute HCL, dilute NaOH and again in acid, with rinsing in between.  Another pair of subsamples was treated with a commercial detergent (1.5 percent SDS), distilled water, 0.1 percent HCL and another detergent (1.5 percent 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. Other cleaning methods followed.

However, a 2005 study refuted this claim, stating that the linen that was tested actually came from a Medieval-era patch applied to the shroud to repair fire damage. A chemist from Los Alamos National Laboratory in New Mexico said that his microchemical tests revealed the presence of a chemical called vanillin in the radiocarbon sample and in the patchwork cloth, but not the rest of the shroud. He claimed that “The fact that vanillin cannot be detected in the lignin on shroud fibers, Dead Sea scrolls linen, and other very old linens indicates that the shroud is quite old,” and estimated the shroud to be between 1,300 and 3,000 years old.

A new study recently published in Scientific Reports analyzed genomic DNA, which was extracted from dust particles vacuumed from parts of the body image and the lateral edge used for radiocarbon dating.

Plant taxa native to the Mediterranean area were discovered, as well as species which originated in Asia, the Middle East, or the Americas, and were introduced in a historical interval later than the Medieval period. The results also speculate that the cloth could have been weaved in India.

Experts say that the DNA evidence allows for two possibilities: the shroud indeed originated in Israel and traveled around the world before winding up in Italy; or the shroud created in medieval Europe, but it was contaminated by worshipers (and plants) from around the globe.

So, despite all these studies, the origin of the shroud is still — and may forever be — a mystery.