Early in my Saga notes I had a tentative plan to add the Gormehghast setting as a mystic destination.
My rough notes suggested that in the Age of Migrations at the fall of the Roman Empire (Western half specifically), one of the last Cult of Mercury “strongholds” (a temple with supporting mundane population, where Gifted wizard-priests fled to from religious persecution), came under threat from an advancing barbarian army/war-band.
The wizard-priests manage to cast a ritual (possibly one of the 38 Great Ritual spells of Plentarch, or maybe a new one delivered by “divine” revelation), and put the entire valley and inhabitants into a Regionne with very limited entry and egress.
In the centuries since the Mercurian wizard-priests occasionally send out one of their number into the mundane world for intelligence gathering and acquiring mercantile goods the regionne needs. I was even thinking that one time this mercer of theirs meets Trianoma and becomes the Founder Mercere (who is magically bound not to reveal Gormenghast)..
I was kind of assuming it was in located in a valley of the Southern Alps, Rhaetio-Roman territory. But now I am not so certain.
Why would a Roman redoubt have such an overtly germanic sounding name as “Gormenghast”? And the ruling mundane have a family name like “Groan”.
Could this be distorted mis-pronounciations of something more (vulgar) Latin?
Also, what other locations might make sense for “Gormenghast” to be located?
Somewhere near the Pyrenees, and the barbarians they fled from were the Visgoths? Or even somewhere near the Atlas Mountains when the Visgoths crossed into North Africa?
Anywhere in the path of Attila the Hun’s rampage?
Somewhere in the Gaulish region as the Salian Franks rise to prominence? Don’t some of the Arthurian romances say he advanced part-way though France intent on Rome?
In the aftermath of the great ritual that hid the valley, the place was known as Oppidum/Templum Carminis Augusti, lit. Redout/Temple of the Great Spell, or simply Carmen Augustum, the Great Spell (in Latin, Carmen can mean song, poem, but also incantation). Over time, linguistic drift turned Carmen Augustum into Carmencustum/Garmengustum, and eventually Gormenghast.
I can’t help with most of this, but your very last question about Arthur going to Rome, that I can answer.
Yes, the British and French versions of Arthur include a long war with Rome. It is early in Arthur’s reign, before the arrival of Lancelot. Roman ambassadors arrive to demand tribute and Arthur tells them the only tribute they’ll get is his spear and, besides, by birth, he is remotely descended from Emperor Constantine, so really he should be emperor.
Rome declares war and the key battles take place in Gaul. Arthur continues to Rome, is crowned emperor, sorts out some political issues and then promptly goes home.
I go into all this detail because Arthur’s expedition to Rome is key to Geoffrey Ashe’s version of the Samarian Hypothesis, an argument that the legend of Arthur is based on historical events surrounding Riothamus, a 5th century king of Brittany and perhaps Britain who led an army into Gaul on behalf of the emperor and died in battle at the town of Deols.
Much love to Ezzelino’s, another etymology could be along the lines of “Roman Geist” if you put it somewhere with a Germanic linguistic thread - the local people who occasionally see it (on the day of the Great Fire of Rome when the moon is full) think of it as a “Ghost of Rome,” hence the name, which evolves in the local consciousness from Roman Geist to Romanghast, and picks up the “Gor” or “Go” or even a “Ko” that mutates, somewhere in the thousand years of history.
The players might know it as Gormenghast at first, as a legend or a rumor or some such. They may learn its proper name, but that way you get the name of your inspiration in there, and honestly the players might keep calling it that anyway, if the other name is less catchy or less easy to say.
As to the “Groan” part - you’ve got at least 500 years of history to play with. Perhaps at one point they realized they needed more people, to keep the gene pool fresh or to show them how to work a new technology. Or perhaps there was a plague and they had to replenish the workforce. Or, maybe there was just someone determined to break in. Or maybe the Priests weren’t interested in the boring hustlebustle of ruling, so they outsourced the job intentionally. One way or another, outsiders got in, and eventually there was enough of an upheaval that someone with the family name “Groan” came into power. (or “power”, assuming the Priest-Mages are still in charge.) If this was a takeover (or a “Takeover”) it might even be by someone knowing the place as “Gormenghast” and making the exonym official, as a means of asserting linguistic dominance over the the Priest-Mages.
I hadn’t been assuming that the Wizard-priests had direct control of the civilian community.
After all they could have been given sanctuary by the local lord.
But now I wonder, how much warning would the Wizard-priests have of the advancing barbarian army? It takes time to setup and perform a Cult of Mercury great Ritual.
Perhaps enough time that the vanguard of the barbarians managed to get close enough to be brought across the Regio with the rest of the valley. Just enough warriors to take control.
Or the local lord had a bodyguard contingent of foederati barbarians, who afterwards decided to change the mundane power structure.
I have been reminded that after Carthage was destroyed in the 3rd Punic War, the Romans rebuilt it in the the time of Julius Ceaser.
Roman Carthage became the 2nd largest city in the Roman Empire. Then it became the capital of the Visigothic Kingdom, then later captured and destroyed by Umayyad Caliphate.
Not knowing the topography of Carthage, would it be too much of a stretch to suggest that Gormenghast could have originated as the quarter of the city that bounded the temple district of Roman Carthage?
I mean, only insofar as it is meant to be surrounded by water on three sides and you’d have trouble doing that in Carthage. That aside, you can put it anywhere you want.