A couple of months ago I found myself by chance at the Welwyn Roman Bath, which just consists of a few low walls and is of relatively little interest except for the fact that it’s in a vault like an air-raid shelter directly beneath the A1(M) motorway (which is totally inaudible). But it reminded me that I wanted to write about Trier, a small town in Germany which was once the capital of the Roman Empire. It’s not that well known today, probably because few of the Roman remains could be excavated until after World War II, and also perhaps because of its position on the far westernmost side of Germany, close to Luxembourg.
The history of Trier
A small Celtic town was conquered by the Romans in the late 1st century (and still claims to be the oldest town in Germany). It was just a local administrative centre (capital of the Civitas Treveroum) until AD 269, when it became capital of the Gallic Empire (not recognised by Rome), governing Gaul, Britannia and parts of Hispania, Germania and Raetia. This lasted just five years before being re-integrated into the Roman Empire, and in 275/6 and 287 Trier was destroyed by Germanic (barbarian) invasions. In 286 the Emperor Diocletian created Maximinian his co-regent, then appointed two more to form a tetrarchy, and Trier became capital of Gaul and an imperial residence (and Trevorum became Augusta Treverorum, meaning The City of Augustus among the Treveri). A palace district, including the Imperial Baths, was created in the eastern part of the present-day city, but work stopped as Constantine the Great (who had spent a lot of time here from 306 to 316) switched his attention to the Eastern Empire. From 328 Constantine II (son of Constantine the Great) was based in Trier; he was Emperor of the West from 337 to 340, followed by his brothers Constans I until 350 and Constantius II until 353. This was a time of revolts, but after 364 there was peace, and Trier saw its heyday under the emperors Valentinian I (who continued building the palace district, completing the baths in 375 – although they were used as barracks) and his son Gratian. Its population may have been as high as 100,000, the same as today. Valentinian II was the last emperor to occasionally reside in Trier, and after 395 Trier lost its importance, as the imperial court moved to Milan and the provincial administration to Arles.
In about 460-470 it was taken over by the Franks and developed steadily as part of the Holy Roman Empire, its bishops becoming archbishops and prince-electors, responsible for choosing the next emperor. One amusing footnote concerns the Synod of Trier (1147) which went a bit wrong when some of the bishops went to Troyes in France instead – it was reconvened in 1148 as the Council of Reims.
France attempted to seize Trier during the Thirty Years’ War, the War of the Grand Alliance, the War of the Spanish Succession, the War of the Polish Succession, and the French Revolutionary Wars – it was captured by France in 1794 and the electoral archbishopric was dissolved, along with the Holy Roman Empire itself, in 1806. At the end of the Napoleonic Wars in 1815, Trier passed to the Kingdom of Prussia, and continued to develop, with industrialisation to go along with the well-established wine industry.
The sights
So what can be seen now? Lots – there are plenty of Roman ruins (and a lot more still to be excavated) and some fantastic churches, which mostly have Roman origins anyway. They’re all part of UNESCO’s Roman Monuments, Cathedral of St. Peter and Church of Our Lady in Trier World Heritage Site, created in 1986 – details are here. The most famous Roman remains are probably the Imperial Baths 
(Kaiserthermen), which cover a wide expanse just south of the city centre, with atmospheric underground passages; there’s a good little museum here. Near the Imperial Baths, a little way southeast of the centre off Spotzmühle, is the amphitheatre – built to seat around 18,000 in the second century, this mostly staged bloody fights, animals against animals, gladiators against animals, and no doubt gladiators against gladiators too.
I was particularly taken by the St Barbara Baths (Barbara-thermen), southwest of the Altstadt on Bäderstrasse, which were built in the 2nd century outside the city walls in the suburb later named after the abbey of St Barbara. Covering an area 172m by 240m, they were the second largest baths in the Roman Empire, and the largest north of the Alps. Abandoned from the 5th century, a church and houses were built inside their walls, and then destroyed in the 17th century, when the Roman stones were taken to build a Jesuit college. Now only the foundations remain, along with various tunnels below, but a modern (free) 
walkway across the site allows you to see the layout of the whole complex, including pools and furnaces and the heating and sewerage systems.
More or less in the city centre, the Forum Baths were discovered only in 1987, when an underground car park was being built – the remains of the two hot-water baths, a cold-water bath, under-floor heating systems and sewers are now roofed over and can be visited from 9am to 5pm except on Mondays. Most of the other sites are open daily from 9am to 4, 5, or 6pm according to the season, and typically cost €4.
In addition, don’t miss the Porta Nigra (Black Gate), on the north side of the Altstadt, towards the station, a massive Roman city gate in which the Greek monk Simeon had himself walled
up as a hermit, dying there in 1034 or 1035. He was made a saint and two churches were built into the gate, one above the other – these were removed, along with the upper story of the eastern tower, in 1804-19, but you can see a model of this rather bizarre hybrid construction in the city history museum next door in the Simeonstift, a former monastery. In addition to a series of plans explaining the city’s development (only in German), there’s a display of sculptures by Ferdinand Tietz (1707-77) around the upper level of the cloister. Anyway, you can walk through and around the gate, while the interior is open in the same way as the other Roman sights.
There are also a couple of quite stunning churches to be seen here. First, the huge Basilica of Constantine, at the east end of Konstanstinstrasse, has an ugly red-brick exterior but a stunning bare interior, no less than 67m long by 26m wide and 33m high – it was built in c310 as the imperial throne room; it was left roofless by the Germanic tribes when they sacked the city, and they built a settlement inside the ruin. It later became a church and the administrative centre of the bishop of Trier, with the apse converted into his residence, until a new palace was built alongside from 1614. In the mid-19th century it was 
restored to its original condition and has been a Lutheran church since 1856 – the usual Protestant lack of internal decoration is ideal to show off the building’s Roman bones. There’s also an optical illusion that emphasises the building’s depth, as the apse’s windows and the niches below them become progressively smaller towards the middle.
The city’s cathedral or Dom is also superb – the oldest cathedral in Germany, it’s built on the ruins of a much bigger Roman church complex and incorporates some walls from a 4th-century church, still up to 26m in height. It was rebuilt in Romanesque style at the end of the 10th and 12th centuries, with Gothic vaults added later. There’s also the Baroque Chapel of the Holy Robe, built to house the Seamless Robe (or Chiton) of Jesus, the one which the soldiers who crucified Jesus cast lots for (rather than ripping it apart), because it was made of one seamless piece of cloth. The Emperor Constantine’s mother, St Helena, supposedly found it in about AD 327 on a pilgrimage to the Holy Land and donated it to the church that Constantine had started building in Trier in 326 (he founded St Peter’s Basilica in Rome the same year, to mark the twentieth anniversary of his reign). The robe was certainly here by 1196, when it was sealed in a new altar, and only removed in 1512; since then it has been displayed to the faithful every few decades, attracting up to a million pilgrims. Normally the robe is hidden away in a reliquary in this chapel, which can merely be glimpsed by processing up behind the high altar of the cathedral – it gives great views down the nave, but is a waste of time in terms of seeing the robe or the chapel of the robe.
Entering through the cloister, you have the Dom on your right, and the Church of the Virgin (the Liebfrauen) on your left – this was built in Early Gothic style around 1200, and is totally different in atmosphere to the rather hectic Dom. It’s much darker (due to the stained glass) and there’s quiet choral music playing, so that tourists and others sit quietly and meditatively.
Changing gear totally, Karl Marx was born in Trier in 1818, and the family house at Brückenstraße 10 is now a museum about his life and writings as well as the history of communism; I’ve seen enough of communism and I didn’t get here. But Roman baths do seem to be a bit of a theme at the moment – in addition to Trier and Welwyn, I recently saw one in Cimiez (in Nice, next to the Matisse museum), and most years I lead a hiking group to the Roman bath house at Ravenglass, which boasts the highest Roman walls in northern Britain, no less than 4m high (I’m being ironic). It was built in about AD c130, as part of a fort guarding the supply line from the port here to the central part of Hadrian’s Wall.
A very few practicalities
I stayed at the youth hostel, which is typically German and efficient; there are some pleasant riverside restaurants nearby, next to the Roman bridge over the Mosel river. Built around 144-152 AD, this is the oldest bridge in Germany, although in fact only the pilings are original and the arches and roadway date from the 18th century. The German army planned to demolish the bridge in March 1945, but a lightning advance by General Patton’s tanks led to its being captured before they had the chance to do so. It now leads to the delightful pedestrian and cycle route along the far bank of the Mosel.