The Shroud of Turin, also known as the Holy Shroud, is a length of linen cloth bearing the negative image of a man. Some describe the image as depicting Jesus of Nazareth and believe the fabric is the burial shroud in which he was wrapped after crucifixion.

First mentioned in 1354, the shroud was denounced in 1389 by the local bishop of Troyes as a fake. Currently the Catholic Church neither formally endorses nor rejects the shroud, and in 2013 Pope Francis referred to it as an "icon of a man scourged and crucified". The shroud has been kept in the royal chapel of the Cathedral of Turin, in northern Italy, since 1578.

In 1988, radiocarbon dating established that the shroud was from the Middle Ages, between the years 1260 and 1390. All hypotheses put forward to challenge the radiocarbon dating have been scientifically refuted, including the medieval repair hypothesis, the bio-contamination hypothesis and the carbon monoxide hypothesis.

The image on the shroud is much clearer in black-and-white negative—first observed in 1898—than in its natural sepia color. A variety of methods have been proposed for the formation of the image, but the actual method used has not yet been conclusively identified. The shroud continues to be intensely studied, and remains a controversial issue among scientists and biblical scholars.

The Gospels of Matthew, Mark, and Luke state that Joseph of Arimathea wrapped the body of Jesus in a piece of linen cloth and placed it in a new tomb. The Gospel of John refers to strips of linen used by Joseph of Arimathea.

After the resurrection, the Gospel of John states: "Simon Peter came along behind him and went straight into the tomb. He saw the strips of linen lying there, as well as the cloth that had been wrapped around Jesus' head. The cloth was still lying in its place, separate from the linen." The Gospel of Luke states: "Peter, however, got up and ran to the tomb. Bending over, he saw the strips of linen lying by themselves."

In 1543, John Calvin, in his book Treatise on Relics, explained the reason why the Shroud cannot be genuine:

In all the places where they pretend to have the graveclothes, they show a large piece of linen by which the whole body, including the head, was covered, and, accordingly, the figure exhibited is that of an entire body. But the Evangelist John relates that Christ was buried, "as is the manner of the Jews to bury." What that manner was may be learned, not only from the Jews, by whom it is still observed, but also from their books, which explain what the ancient practice was. It was this: The body was wrapped up by itself as far as the shoulders, and then the head by itself was bound round with a napkin, tied by the four corners, into a knot. And this is expressed by the Evangelist, when he says that Peter saw the linen clothes in which the body had been wrapped lying in one place, and the napkin which had been wrapped about the head lying in another. The term napkin may mean either a handkerchief employed to wipe the face, or it may mean a shawl, but never means a large piece of linen in which the whole body may be wrapped. I have, however, used the term in the sense which they improperly give to it. On the whole, either the Evangelist John must have given a false account, or every one of them must be convicted of falsehood, thus making it manifest that they have too impudently imposed on the unlearned.

Although pieces said to be of burial cloths of Jesus are held by at least four churches in France and three in Italy, none has gathered as much religious following as the Shroud of Turin. The religious beliefs and practices associated with the shroud predate historical and scientific discussions and have continued in the 21st century, although the Catholic Church has never passed judgment on its authenticity. An example is the Holy Face Medal bearing the image from the shroud, worn by some Catholics. Indeed, the Shroud of Turin is respected by Christians of several traditions, including Baptists, Catholics, Lutherans, Methodists, Orthodox, Pentecostals, and Presbyterians. Several Lutheran parishes have hosted replicas of the Shroud of Turin, for didactic and devotional purposes.

Although the shroud image is currently associated with Catholic devotions to the Holy Face of Jesus, the devotions themselves predate Secondo Pia's 1898 photograph. Such devotions had been started in 1844 by the Carmelite nun Marie of St Peter (based on "pre-crucifixion" images associated with the Veil of Veronica) and promoted by Leo Dupont, also called the Apostle of the Holy Face. In 1851 Dupont formed the "Archconfraternity of the Holy Face" in Tours, France, well before Secondo Pia took the photograph of the shroud.

MIn 1389, the bishop of Troyes sent a memorial to Antipope Clement VII, declaring that the cloth had been "artificially painted in an ingenious way" and that "it was also proved by the artist who had painted it that it was made by human work, not miraculously produced". In 1390, Clement VII consequently issued four papal bulls, with which he allowed the exposition, but ordered to "say aloud, to put an end to all fraud, that the aforementioned representation is not the true Shroud of Our Lord Jesus Christ, but a painting or panel made to represent or imitate the Shroud ". However, in 1506 Pope Julius II reversed this position and declared the Shroud to be authentic and authorized the public veneration of it with its own mass and office.

The Vatican newspaper L'Osservatore Romano covered the story of Secondo Pia's photograph of 28 May 1898 in its edition of 15 June 1898, but it did so with no comment and thereafter Church officials generally refrained from officially commenting on the photograph for almost half a century.

The first official association between the image on the Shroud and the Catholic Church was made in 1940 based on the formal request by Sister Maria Pierina De Micheli to the curia in Milan to obtain authorization to produce a medal with the image. The authorization was granted and the first medal with the image was offered to Pope Pius XII who approved the medal. The image was then used on what became known as the Holy Face Medal worn by many Catholics, initially as a means of protection during World War II. In 1958 Pope Pius XII approved of the image in association with the devotion to the Holy Face of Jesus and declared its feast to be celebrated every year the day before Ash Wednesday. Following the approval by Pope Pius XII, Catholic devotions to the Holy Face of Jesus have been almost exclusively associated with the image on the shroud.

In 1936, Pope Pius XII called the Shroud a "holy thing perhaps like nothing else", and went on to approve of the devotion accorded to it as the Holy Face of Jesus.

In 1998, Pope John Paul II called the Shroud a "distinguished relic" and "a mirror of the Gospel". His successor, Pope Benedict XVI, called it an "icon written with the blood of a whipped man, crowned with thorns, crucified and pierced on his right side". In 2013, Pope Francis referred to it as an "icon of a man scourged and crucified".

Other Christian denominations, such as Anglicans and Methodists, have also shown devotion to the Shroud of Turin.

In 1983 the Shroud was given to the Holy See by the House of Savoy. However, as with all relics of this kind, the Roman Catholic Church made no pronouncements on its authenticity. As with other approved Catholic devotions, the matter has been left to the personal decision of the faithful, as long as the Church does not issue a future notification to the contrary. In the Church's view, whether the cloth is authentic or not has no bearing whatsoever on the validity of what Jesus taught or on the saving power of his death and resurrection.

Pope John Paul II stated in 1998 that: "Since it is not a matter of faith, the Church has no specific competence to pronounce on these questions. She entrusts to scientists the task of continuing to investigate, so that satisfactory answers may be found to the questions connected with this Sheet."[64] Pope John Paul II showed himself to be deeply moved by the image of the Shroud and arranged for public showings in 1998 and 2000. In his address at the Turin Cathedral on Sunday 24 May 1998 (the occasion of the 100th year of Secondo Pia's 28 May 1898 photograph), he said: "The Shroud is an image of God's love as well as of human sin ... The imprint left by the tortured body of the Crucified One, which attests to the tremendous human capacity for causing pain and death to one's fellow man, stands as an icon of the suffering of the innocent in every age."

On 30 March 2013, as part of the Easter celebrations, there was an exposition of the shroud in the Cathedral of Turin. Pope Francis recorded a video message for the occasion, in which he described the image on the shroud as "this Icon of a man” and stated that "the Man of the Shroud invites us to contemplate Jesus of Nazareth." In his carefully worded statement Pope Francis urged the faithful to contemplate the shroud with awe, but "stopped firmly short of asserting its authenticity".

Pope Francis went on a pilgrimage to Turin on 21 June 2015, to pray before, venerate the Holy Shroud and honor St. John Bosco on the bicentenary of his birth