The Udoxia of Jhaamdath are powerful magical artefacts that helped establish and preserve the empire for a millennia where they were worshipped as the embodiment of the gods of Jhaamdath.
History records that the first Udoxia is mentioned in -5725 DR, when Laszik Silvermind presented the first Udoxia to the people of Jhaamdath and set out the vision of civilization as communicated to him by the god Auppenser.
Over the following decades Laszik created a number of Udoxia and bequeathed them to the people of Jhaamdath to help guard the cities of the Sword (as the Vilhon Reach was then known), as new cities were established a Udoxia was laid at its centre to protect it and promote the growth of the Invisible Art.
Originally six Udoxia were created, for only 6 Cities of the Sword were ever supposed to exist (according to the Code of Auppenser). Eventually Jhaamdath outgrew its cities and more than 12 cities were created in the Vilhon, each of which contained its own Udoxia, so at some point the Council of Exarchs learned how to create new Udoxia.
Over the centuries the Udoxia remained fairly stable as the foundation of every major city in Jhaamdath, until -273 DR when the Emperor Dharien began to confiscate them, beginning first with those held directly inside temples to Auppenser, and later those held by individual cities (culminating in the bloody sacking of the city of Gharrent).
The tsunami created by the elves of Nikerymath destroyed any evidence of what happened to the Udoxia and from that point they were lost to history and have never been seen since, despite hundreds of expeditions from various treasure hunters over the last millennium.
The entire recorded history and purpose of the Udoxia is a lie. Laszik Silvermind did not craft the Udoxia, he stole them from his patron and great grandsire; the ruby dragon Auppensaradior. They are not artefacts at all, but really dragon eggs that contain Auppensaradior’s offspring, and Laszik held Auppensaradior to ransom using these eggs, demanding his obedience in exchange for the egg’s continued existence.
Laszik stole the eggs to guarantee the non-interference of a powerful being that had been manipulating the people of the Rezamark (Shining Plains) for millennia, but also because the dragon eggs absorbed all magic cast into them and stored it like a gigantic battery. those attuned to the eggs could retrieve that magic over a large distance (several miles) and use it to power whatever spell they desired, allowing them to cast a greater number of spells and at greater power than their abilities would otherwise allow.
Laszik also had an ulterior motive for stealing the Udoxia. Laszik himself had escaped Oryndoll in his youth and stole a number of their secrets when he fled. The Udoxia saturated the area around them with magic and so obscured any attempts to scry, thus Laszik was able to mask his presence and the signature of illithid magic in Jhaamdath for many hundreds of years.
Using these Udoxia, Jhaamdath was able to secure the safety of its cities from internal and external threats. Over time, those charged with caring for the eggs forgot the secrets of them and found that an intelligence lurked inside the eggs, they began to worship these eggs as gods and it is from this that the core of the Jhaamdath Pantheon was born.
By pooling magic into the eggs (casting spells at them so that they absorb them) the Psiarchs of Jhaamdath nourished the dragons inside by increasing the richness of the magical yolk that surrounded them, however, with an abundance of food, the developing dragons remained dormant for thousands of years, enhancing their magical abilities but remaining unhatched for millennia longer than normal.
When Emperor Dharien confiscated the Udoxia, the worship and storing of magical energy suddenly stopped, within a century the unhatched dragons had exhausted their magical yolk and began to hatch. Some escaped their imprisonment, catching their captors unawares, others were twisted by the experiments the emperor had subjected them to, others remained unhatched and were used in the defence of the remnants of Jhaamdath by unscrupulous survivors which exhausted the dragons inside and caused their destruction.