A cloth image of Christ's face was venerated at Rome from the early medieval period, and by the high Middle Ages the Veronica had become one of Western Christendom's most important pilgrimage relics, reproduced endlessly as the small badge, the vernicle, that pilgrims wore to show they had seen it. Rome's claim to the authentic Veronica has never gone unchallenged: other European churches, including a chapel in the Italian town of Manoppello and a tradition once associated with Jaen in Spain, have separately claimed to hold the genuine cloth or a more legible copy of it, disputes the Fabbrica has not attempted to adjudicate on behalf of the wider Church.
Complicating matters further, the relic's condition itself is now a significant part of the controversy: the image on the St Peter's cloth is reported by the small number of people who have examined it closely over the centuries to be extremely faint or largely indistinguishable, a state some historians connect to a poorly documented disruption during the basilica's Baroque-era rebuilding, when the relic's precise custody and display arrangements were altered along with the pillar architecture around it. Because the Fabbrica displays the veil only briefly, once a year, from a considerable height and distance, and permits no close photography, independent modern assessment of what the image actually shows, let alone its authenticity, remains essentially impossible, a restriction the Fabbrica maintains as consistent with the relic's traditional and devotional rather than exhibitionary purpose.