An Arden Vul Theogony
One interesting thing about the world of Arden Vul, Magae, is that it is polytheistic with very clear and obvious stand-ins for the Ancient Greek gods, up to and including having a goddess of wisdom and battle whose main symbol is an owl and a spear, yet its chief god is not the Zeus stand-in. In fact, he - called Treshub - is branded as "Chaotic Evil".
Luckily for us, I have access to some of the finest surviving Archontean accounts of the time period which the game takes place, and so I've attempted to make sense of it through a theogony. It goes without saying that the empire is wide and populous and that there are likely a hundred variations of these stories, but this is the one I'm aware of. It is periodised into five great ages.
The Creation
Sometimes called simply "once upon a time". It is in these days before days when the Archonteans believe the essential underlying reality came to be - called Kaerion, or "the" Kaerion, which a Neoplatonist might call the Monad. Kaerion is depicted variably and not always anthropomorphised (as indeed all Archontean deities), but always as a bald person, often holding a staff or, some say, a plumb line.
There are many tales of what or who might have been born from Kaerion, such as Night (Ellion) or the savagely beautiful underworld (Chibalba). This time is periodised as the infancy of the world, when elements were still being created from one another and when humanity was still fumbling around in search of civilisation - a major concern of the Archonteans. Eventually, they found it.
The Age of Magic
Ancient and modern Archontean accounts correlate dragons with magic in some undefined yet self-evident fashion. Dragons came about, and men were able to say things into existence, and you would be a fool to ask why these things are related - yet a philosopher would require at least a full year to prime you into the specifics.
At this time, humanity lived under the dragons and the accounts are bittersweet. Dragons are wondrous yet dangerous, and their great and terrible age is no differently "remembered" (if indeed it is a memory at all). Tales of what happened in those days abound: in those days men were born giant and threw many large seeds, and this is why the Grain Islands exist; in those days men were born together with women until a dragon ripped them apart and so they search for their other half; it was in those dragon days when rain fell for the first time, due to a war between a dragon in the the ocean and a dragon in the sky which rages to this day, etc.
Most importantly, however, it was in those days that the city of Archontos was founded, and not long thereafter when one of its scions, Ennius, became the first emperor. He was helped by a group of deities, among which Houranos1 (the sky) and Atashak (the sun which shines upon a battlefield) and others which are still known yet not famously worshipped, which shackled the dragons and harnessed their power, as well as gave order to things. The elements, the very underpinnings of the world, were stabilised by the presence of the Archontean Empire and its godly emperor, who is also one of the gods but simply remained in this layer of existence so as to help shepherd humanity.
The Golden Age
Also known as the Heroic or Titanic Age, this is mythologised as the time when the empire was at its most powerful, long ago, before history began. Tales of great heroes and great wars are typically put here, and it is from this time whence the great constructions are believed to come from.
Whether the city of Arden Vul comes or not from this period is a matter difficult to philosophers, who already have long debates regarding whether or not this period is indeed meant to be regarded as existing or rather as a long metaphor to the state of the soul and being. Regardless, if taken literally, it is in those days that the heroes Arden and Vul likely lived and founded Arden Vul.
The Storm Age
It was prophesised that the reign of the Titans would not last forever, for one of their children would overthrow them, and so he did. Zeus2, the feisty god of storm and lightning, connived a war between the gods. So powerful were they that much was destroyed - a great flood was raised and even the foundations of the city of Archontos, the very centre of reality and civilisation, were rocked. From the ashes emerged Zeus and a new cohort of deities, his brothers and sisters, who ruled as petty and destructive kings of nothing.
Yet this too could not last, for it was prophesised that the rule of Zeus would end and that the world would be healed by Zeus' firstborn. Afraid of having done to himself what he did to his forefathers, Zeus swallowed Metis whole, his pregnant human wife, but this did not prevent her from giving birth inside of him. From his cloud-gathering head burst forth Athena3, fully grown and armed, and this made Zeus go mindless. Now he comes periodically and rages blindly against the earth, hurling lightning bolts, but he always goes away.
Another titanic war was raged, this time between Athena and her cohorts - which included Mitra the Lion of Justice, but also Heschius Ban who tramples on all - and Zeus and his cohorts, and so the world was reshaped once more.
The Archontean Era
Athena is believed to preside over current history - or as far back as the Archonteans can remember, anyway. She is wise and inventive, and thus she loves order and record-keeping. It is said that the war against the Tyrant Zeus destroyed much of the good and beautiful things from the Golden Age, and that much of their knowledge and magic was lost, but since all knowledge resides inside of Athena's mind, it stands to reason that it can all be found or invented once more.
Thus, the Archonteans strongly believe that they live in days which, while greatly diminished from days past, are still en route to the restoration of the world - and for that, the full breadth of the Empire must be restored too.
A second opinion
All that was presented here was the Archontean point of view. What of the Thorcinga? They have an intimately close relationship to the Archonteans and there are many indications that they preserve stories from back then. In fact, many Thorcin and Archontean philosophers see Father Utar, Lord of the Eyes, as a syncretic remnant of the Zeus cult in Irthuin; except instead of conceiving of him as a tyrant which tore down the empire, they think of him as an easily foiled patriarch. His brother Sherlosh harkens back to Zeus' brother Poseidon, since both have tridents; and it is widely accepted that Laraveen is an aspect of Athena, though one with more concern about building rather than battle.
The Thorcinga are generally uninterested in creation myths, having a few that involve Ghareela and Ghureena alternating in creating good and bad things, but their primary concern is how did they come here, thus few Thorcin scholars have dedicated themselves to untangling this knot. Thus, the responsability falls to the intrepid and foolhardy who are willing to plunder the depths of The Halls of Arden Vul.