Trier claims the seamless tunic that the Gospel of John says the soldiers did not divide but cast lots for, and the claim runs through Helena, mother of Constantine, who is said to have brought it from Jerusalem to the city where she had lived. That tradition is medieval. It is not recorded by anyone at the time it describes, and the earliest secure documentation of a robe at Trier is from 1196, when the archbishop translated relics into the new high altar of the cathedral.
After that it was largely out of sight until 1512, when it was rediscovered and shown in the presence of the emperor Maximilian, and the modern history of public showings begins there. They have been rare and irregular ever since, at intervals of decades, in 1810, 1844, 1891, 1933, 1959, 1996 and 2012, and each has drawn very large numbers of pilgrims.
The object itself is difficult to examine. Centuries of well-meant conservation have left it patched, backed and impregnated with later materials, so that what a visitor sees is a garment-shaped composite in which the original textile is largely inaccessible. Scientific examination has therefore been limited, the diocese does not present the relic as authenticated, and recent pilgrimages have been framed around veneration and pilgrimage rather than around any claim of proof.