The Cathedral of Trier is a Roman Catholic church, and it is the oldest bishop’s church in Germany.
It is also considered to be the largest church in Trier (112.5 m length by 41 m width). Today, the cathedral is an important Catholic shrine that still receives pilgrims from all over the world. It houses the “Holy Robe,” the relic which presumably contains fragments of the tunic of Jesus Christ. According to Wikipedia, it was raised upon the foundations of Roman buildings of Augusta Treverorum.
Today, the cathedral stands above a former palace from the period of the Roman Emperor Constantine the Great. In the 4th-century, the current palace was replaced by a larger Christian church from ancient times. There are remains from the late 3rd-century of the first Early Christian room north of the Alps which can be seen under the building of the Cathedral. In the Middle Ages, one of the seven electors of the Holy Roman Empire, Archbishop of Trier, was an important ecclesiastical figure that controlled the land from the French border to the Rhine region.
Because of him and his successors, the cathedral today is still beloved as one of Germany’s greatest historical-Christian treasures regardless the long gone authority of the archbishops, ended by Napoleon in the 19th-century.
The most important relic in the cathedral is the “Holy Robe” of Christ which was brought there by the Empress St. Helena, mother of Constantine the Great when she visited the Holy Land. The first mention of the robe appears in written documents from the 12th-century, and three hundred years later, the Robe was found inside the cathedral when the high altar was opened.
The relic was kept folded, and no one was not allowed to see it. In 1512, the relic was finally shown when Emperor Maximilian I demanded to see it. After that, many pilgrims came to the cathedral to see the Robe. In 1996, the tunic was seen by over one million pilgrims and visitors.
Today, the relic is kept in an annex, and it is rarely shown to the public.
Other important relics are the skull of St. Helena, the Holy Nail (believed to be one of those used in the Crucifixion of Christ) and the sandal of St. Andrew which are displayed inside the cathedral. The Cathedral of Trier was listed UNESCO World Heritage Site as part of the Roman Monuments, Cathedral of St. Peter and Church of Our Lady in Trier.