Trier

Trier was a capital of the western Roman empire in the fourth century, and Constantine held court there. The audience hall he built, a vast brick basilica with a semicircular apse and no aisles, still stands and has been a Protestant church since the nineteenth century, so a Roman throne room is now used for Lutheran worship. Beside it, a double cathedral was laid out on ground that had held an imperial residence, and the present cathedral incorporates Roman masonry in its walls.

The city claims the oldest bishopric in Germany, with a list of bishops beginning in the third century, and the claim is credible for a place of that importance in that period. Athanasius spent part of his exile there and is generally supposed to have introduced western readers to Egyptian monasticism as a result, an encounter Augustine later recalled as decisive for two officials at the court.

Trier's archbishops became electors of the empire, with a vote in choosing the king, so the see carried temporal weight for centuries. The Porta Nigra, the Roman gate, was turned into a church after a Greek hermit named Simeon had himself walled into it in the eleventh century and was venerated after his death, and the church was stripped back to the gate again under Napoleon, which is why the building looks Roman today.

Trier cathedral keeps a garment venerated as the seamless tunic that the soldiers at the crucifixion cast lots for rather than divide, as the gospel of John describes. Tradition attributes its arrival to Helena, the mother of Constantine, who is associated with the city and credited with recovering relics of the Passion in Jerusalem. Documentary evidence for the robe begins much later, in the twelfth century, and the textile itself has been repaired and encased so often that little of the original fabric is accessible. The church has never pronounced on its authenticity, and the diocese presents it as an object of devotion rather than as a proven relic.

It is shown rarely. Great pilgrimages were held in 1512 at the emperor's request and at intervals since, with showings in 1933, 1959, 1996 and 2012, each drawing hundreds of thousands.

The exposition of 1844 had a consequence nobody intended. Half a million pilgrims came, and a Silesian priest named Johannes Ronge published an open letter denouncing the whole business as idolatry and superstition. He was excommunicated, and the movement that gathered around him, the German Catholics, formed congregations across the German states with a rationalist programme and lay governance. It was absorbed into free religious associations later in the century, but for a decade a relic in Trier had produced a national schism.