Salvete amici, it’s me, Aelius Rufus. Yes, it is quite some time you last saw me, and I had to have a word with Gabriele about the lack of Roman posts. She’s always traveling to those barbarian places, first the Mare Suebicum and then into the lands of the Hermunduri and other, more obscure tribes. Really, no sane Roman goes there. And those posts about old rocks – not even the Greek philosophers believe the world is that old. And when she’s not traveling, she’s writing. Fiction, of all things, and not even trying to disguise it as a true account. 😉

But well, I got her to transfer what I told her about the Porta Nigra in Augusta Treverorum into this funny thing with the screen which everyone everywhere can read, she says. Oh, and she also tells me she has not many pictures this time, because it was the first time she used that little picture box and didn’t take as many magic drawings as she does now.

Porta Nigra, the town side
Ok, so here we go. The Porta Nigra is one of the best preserved gates from Antiquity, and the people in Augusta Treverorum are still proud of it; not to mention visitors who want to see the gate leave some money in the town.

Like most other buildings, the gate dates to the 2nd century AD and was planned as part of the expansion program under the Emperor Antoninus Pius. The town was walled in and got five flashy gates of which only the Porta Nigra survived. I’ve already mentioned Tony’s construction activities in this post.

Porta Nigra, seen from outside the Roman town
The Porta Nigra wasn’t black back then, though instead the colour of sandstone, but all the smoke tinted it dark (environment problems are not a 21st century thing). Of course, it wasn’t called the Black Gate back then, either (and why does Gabriele now murmur something about Mordor?) – that name is first mentioned in 1041. The original name was likely Gate to Confluentes (Koblenz), and for a time it was called Porta Martis, Gate of Mars.

It looks huge, but the size is actually Standard Roman Din-A-Gate: 36 metres wide and 21.5 metres deep in the centre of the oblong towers; the towers were 32 metres high (the west tower is still almost the original size), the middle building, the gate proper, 24.5 metres. The foundations are 4 metres wide, the walls up to 3.4 m. The gate was integrated into the town wall (which – another number for Constance *grin* – was 6.4 km long), the battlements of the walls ran at 6 metres above ground and were accessible from the gate towers.

From the landside, the Porta Nigra with its protruding towers must have looked impressive to visitors and enemies alike.

They way through the gate
The inner yard between the two towers is framed by two galleries which could be reached by timber staircases – one of those has been repaired for visitors to get to the galleries. The outer gates could be locked by a portcullis. The inner gates should have been protected by wooden doors but those were never installed. If finished, the whole contraption would have kept enemies who breached the outer gate locked inside the yard where they could have been sH๏τ by missiles from the galleries. But as it is, the inhabitants of Augusta Treverorum could be glad no enemy ever made it through the gate because else they’d just have run onward into town.

They might even have found shelter from the rain, since the main roads in Trier, including the one leading off the Porta Nigra, were framed by pergolas. That’s more than you get today in the way of comfort.

The arcades around the yard (first floor)
The missing doors are not the only unfinished part of the Porta Nigra. A lot of the large sandstone squared stones (weighing up to 6 tons) that were used for the facing have only been roughly hewn on the outside. The ground facets where they fit together have been well smoothed, though, so that the stones stay put without mortar or opus cemenтιтium. Some traces show those archaeologists who poke around in our buildings that the stones had been worked with water powered bronze saws. Iron clamps babbitted in lead had been added nevertheless, but those have been plucked out during the Middle Ages; it made no difference to the walls.

From the town side, the gate would almost have looked like a palace, but most of the decorative pillars, capitals and bases are only roughly hewn as well, which is surprising in a grand building like the Porta Nigra which was clearly intended to impress visitors and show off the wealth of the town magistrates.

The town walls, of which almost nothing remains save some traces only the archaeologists from Gabriele’s time can read (how do they do that; some sort of time traveling?), had been erected on a grand concept, too, with two facing walls filled by the usual Roman mix of mortar and ashlar. The careful craftmanship of those walls clearly shows that they had been built in a peaceful time. One part of the wall (45 metres in the south side) remained unfinished to give access to the area of potteries outside town, and that part was later built in a much more haphazard manner. Some of Gabriele’s ancestors were milling outside Trier then. The walls were additionally protected by a series of trenches.

Porta Nigra inside, one of the rooms later used as chapel
So the question remains why the Porta Nigra has never really been finished. That includes trying to find the exact date when it was built, which seems to be a bit of a puzzle for those archeologists. But there are a few hints. Those archaeologists love them some pottery shards and they found plenty of those among the rubble of the collapsed town walls, dating to the time of the reigns of Antoninus Pius (138 – 161), Marcus Aurelius (161-180), Commodus (180 – 192) and maybe Septimius Severus (193 – 211; likely the first years). A few statistics have been calculated about the time it would have taken to erect the gate, but I’m prone to go for one of the longer estimates; governmental projects were never finished in time. I see Gabriele nods.

One of the reasons could have been that the magistrate of Trier ran out of money and none was forthcoming from the emperors, either (Marcus Aurelius was busy fighting the Marcomanni at the Danube among others, and Septimius Severus had to fight contenders for the position of emperor).

The arcades around the yard, closeup
But it’s not impossible that hostile actions got in the way of fine-tuning those stones and pillars. In AD 162, the Chatti crossed the Rhine and raided the province of Germania Superior (around Mainz, for those who slept during their geography lessons), in 175, the Chauci in northern Germany did the same and raided the provinces of Germania Inferior and Gallia Belgica, to which Trier belongs. The inhabitants of the town may have thought it more prudent to dig another trench and fill in that gap in the wall than polishing a few decorative pillars. If the Chauci ever laid siege to Trier, they didn’t succeed; siege warfare was not the strength of the Germanic tribes. (I know, Aelius, we would have needed Constance and her trebuchets, lol.).

The man to repel the Chauci was the governor of Gallia Belgica, Didius Julianus, who was made consul for his gallant defense of the province. He would later become emperor for nine weeks by paying for the job during the Year of the Five Emperors after Commodus’ death in AD 192. He was executed by the victorious Septimius Severus.

Porta Nigra, a hall later used a church
Another contender for the imperial purple at the time was Clodius Albinus, governor of Britannia. At first, Septimius Severus, who had another rival in the east to deal with, made an agreement with Albinus, offering him the position of caesar and heir, but when he had defeated the rival, he wanted to establish his own sons (the brothers Geta and Caracalla) as heirs. As a consequence, Albinus, who had some support in the Senate in Rome, took his three legions from Britannia and crossed over to Gaul where he was acclaimed emperor by the troops, defeated the legionary legate Virius Lupus, and made his headquarter in Lugdunum (Lyon).

But he failed to gain the alliance of the Rhine legions. The XXII Primigenia stationed in Mainz came to the relief of Trier when Albinus besieged the town in AD 196, and the following year, Albinus was defeated at the Battle of Lugdunum, and either fell or was executed upon orders of Septimius Severus, and condemned to damnatio memoriae, oblivion of memory. Severus also executed some senators who had supported Albinus, and from that time on he was the uncontested emperor.

Interior, pᴀssage way
A sidenote from my time-travelling friend Merlinus: When Albinus took most of the Roman army with him to Gaul, the tribes north of the Hadrian’s Wall promptly raided the province, and Severus sent the same Virius Lupus who had been defeated in Gaul, to restore order – which he did by buying peace. Not exactly Severus’ idea, so he would later come to Britain himself and show those northern tribes what a Roman army looked like.

For some reason, the gate was not finished after those wars, either. Maybe money was indeed the issue then.

Another view of the Porta Nigra seen from the town
Trier escaped most of the German raids in the 3rd century since it was too far in the hinterland. But it became the residence of the Gallic Empire (Imperium Galliarum) in AD 271 when one of those wannabe emperors, Tetricus, moved his base there. He deemed it safer, despite the unfinished gate.

The Gallic Empire (which included Gaul, the Roman occupied parts of Germania, and Britannia) had been founded by Postumus – or the soldiers who proclaimed him emperor, to be correct – in AD 260. Things had gotten pretty pear shaped in the east when the Sᴀssanids captured the emperor Valerian in AD 260, leaving a a power vacuum and a bunch of quarreling parties. The result were several emperors who lasted about as long as the coach of a soccer team that keeps losing its league matches (says Gabriele; I have no idea what soccer is). No wonder the legions at the Rhine prefered a closer-to-home solution. But Postumus was eventually ᴀssᴀssinated (AD 268), and his successors lasted not longer than those metaphorical soccer coaches, either. The emperor Aurelian put an end to the extra emipre in 274.

Porta Nigra at night
Augusta Treverorum, then called Treviris, turned out to be a good site for an administrative centre of the diocesis Galliarum. The town got an additional boost when the emperor Constantine took a liking to the place and made it one of his residences between 306 – 324. The Imperial Baths date to that time. His son, another Constantine, spent a lot of time in Trier as well, as did several emperors in the 370ies to 390ies.

But after the provincial government was moved to Arles and Britain abandoned (AD 410) Trier lost its importance. The seat of the bishop and the Gallo-Roman upper class continued to keep the Roman tradition alive, though, despite several German attacks that destroyed part of the town.