Miracles validated relics and drew healthy pilgrims looking for their tickets out of Purgatory. Pilgrims brought cash with them, so the curators of shrines had good reason to promote successful episodes of healing. It may have been the effectiveness of these marketing operations that determined whether the devout deemed the Holy Blood in Hailes more worthy of a visit than the example at Westminster Abbey. Authenticity was also helpful. England's greatest pilgrimage centre was the shrine of St Thomas Becket at Canterbury. No one doubted that the martyred archbishop's body really did lie there. 

Margery Kempe, whose spiritual autobiography was rediscovered in 1934, was wealthy enough to go on many pilgrimages. The main routes were lined with inns, making them among the more comfortable itineraries for travellers during the Middle Ages, although not without their hazards. Innkeepers were especially notorious for robbing and murdering pilgrims. This is one of the reasons that Geoffrey Chaucer's group of pilgrims to Canterbury found safety in numbers. Margery Kempe herself journeyed all the way to Jerusalem in 1414, although her ecstatic fits and weeping drove the rest of the company to distraction. Unperturbed, she also completed pilgrimages to Germany, Spain and the Baltic.

Relics do not necessarily have to be bones or bodies. Because both Jesus and his mother, the Virgin Mary, are supposed to have ascended bodily to heaven, remnants of their earthly lives could not consist of parts of their corpse. Fragments of the true cross, the crown of thorns and even the Virgin's milk were all touted to pilgrims. Linking Christ to the Virgin directly, Treasures of Heaven even features a reliquary for Jesus's umbilical cord. But the most interesting of these secondary relics are the various images of Christ or Mary. The Turin Shroud is well-known and still revered despite Carbon 14 techniques dating it to around 1300. If this is not the burial sheet of Jesus then it is, at least, a fine example of medieval art. 

Other images are almost as celebrated. The icon of the Virgin of Vladimir, now housed in Moscow, is one of many said to have been painted by St Luke. The prolific apostle's artistic achievement is all the more remarkable for perfectly imitating an iconographic style dating from some 1,200 years after his death. Other pictures claim to have a miraculous origin. The legend of Veronica, who handed Jesus a cloth to wipe his brow and was rewarded with a likeness of his face imprinted on the fabric, is well known. Treasures of Heaven includes another icon allegedly not produced by human hands. The catalogue blandly states that its date and place of composition are unknown. This faint image is the Mandylion of Edessa. Or one of them.