A linen cloth over four metres long carries a faint double image, front and back, of a man laid out after a scourging and a crucifixion. Its documented history begins in the 1350s at Lirey in France, where a local bishop shortly afterwards wrote to the pope that the cloth was being exhibited for gain and that an artist had confessed to producing it. It passed to the House of Savoy, survived a fire at Chambery in 1532 that left melted silver marks and patches sewn by nuns, and came to Turin in 1578, where it has been kept ever since.
Interest in the modern sense began in 1898, when a photographer permitted to record it found that his glass negative showed a far clearer and more natural image than the cloth itself, which is to say the image behaves like a photographic negative.
In 1988 a sample was divided between three laboratories, which independently dated the linen to between about 1260 and 1390, a result consistent with the documentary record. Supporters of authenticity have argued that the sample came from a repaired corner or was contaminated, and textile and imaging studies have continued in both directions since. The Catholic Church has never declared the cloth authentic. Popes have described it as an icon and a mirror of the gospel and left the question of its origin to science, and it is exhibited publicly only at long intervals.