Turbela

Sector capital of the Vigilius sector and a Hive world. Lying near the center of the Vigilus sector it holds an important location as a communications and transportation center. Holding a heavy Imperial and Mechanicus presence it is the most heavily fortified planet in the sector.

Pre-Imperium
Settled during the Dark Age of Technology, nearly 200 Hive cities are scattered through the world in clusters of ten, boasting a total population of ~90,000,000,000 though the loss of trade for food during the Age of Strife led to a sharp drop in population. The vast areas of land between the clusters are thought to have been originally intended for farmland, but soon became a waste due to the extreme amount of pollution put out by the Hive cities. Before the coming of the Emperor, these Hive cities were ruled by Priest kings who are thought by the modern Imperium to have been psykers of some sort. In the decades leading up to the arrival of the Great Crusade, the Priests began having visions of great armies being led by a magnificent golden god.

Coming of the Imperium
When the expeditionary fleets arrived, they were greeted by the Priest Kings of Turbela who inquired of them if they knew of this golden god. After the expeditionary fleet leaders showed them various pict caps and remberancer paintings of the Emperor, the Priest-Kings became convinced that the Emperor was the god they had had visions of and petitioned for entry. The Expeditionary fleets, eager to add another world to the growing Imperium offered not only entry, but trade with agri-worlds to help sustain the populations and allow it to grow once more. Their only condition was that the planet adopt the secular Imperial Truth and abandon their god worship. To the Priest-Kings it would mean losing one of their most effective ways of controlling the populace to some, and outright blaspheme for others. When they voiced concerns however the Expeditionary fleet merely pointed out that they could easily be replaced and that most of the population called for joining the Imperium. Faced with this threat, the Priest-Kings met in secret and agreed to bide their time for when the Imperium would be more open for religion before publicly agreeing to the terms offered by the Imperium.

When the Imperium and Mechanicus examined more closely however, they found something far more valuable than a source of manpower. Scattered across the surface of the planet, but mostly congregated near hive cities, were large building shaped like geometric objects, (pyramid, cube, etc). Upon examining them, the Mechanicus found to their delight that they were storage depots that had been sealed during the Dark Age of Technology. Many had already been plundered and opening the remaining ones proved difficult. The first one, broken into by forcing the doors, activated a anti-matter bomb trap that not only obliterated the building, but vaporized everything within a seven mile radius. The second one however, in which they drilled through the walls merely activated a complex and deadly security system that took over a year to deactivate. What they found inside however was more than worth; while having been primarily some kind of food/seed depot, there were still remains of archeo tech relatively intact. After the discovery however, the Arch-Magos in charge of the investigation declared that, in order to avoid risking destroying the sacred treasures within, they would only open further vaults the way they were meant to be opened. Given how the opening mechanisms themselves were complex pieces of archeo tech, this meant it would likely take centuries or even longer. In order to protect their discoveries, the Mechanicus built numerous planetary defense weapons across the planet and even on the planet's four moons (all around a 600 km diameter range). Even by the 41st millennia many vaults remain unopened, each one's opening being the result of centuries of work. After the Volhar tech heresy, it goes even slower as the risk of corrupted machines becomes apparent.

Horus Heresy
During the Horus Heresy, the Vigilius sector would side with the Imperium, but provide no significant support. On Turbela, word of the Heresy had sent the Mechanicus into a flurry of fortifying and preparing, lest the Traitor forces try to come and claim the relics still entombed. Thus, on Turbela, the whole Heresy was spent preparing for battles that never came.

Their only real contribution to the Imperium during the Heresy was their offer of fuel and new crew members to Imperial Naval vessels that passed through. One of these ships would bring with it an item that would change the course of Turbela's future. A copy of the Lectitio Divinitatus, possibly one of the original copies, passed from the ship's captain to one of the former Priest-Kings. While merely a curiosity to the ship captain, to the Priest-Kings of Turbela it served as proof that their faith had been correct. Still wary of enforcement of the Imperial Truth, the Priest-Kings began to produce copies and distribute them. At first, only in secret and to select people such as nobles, then as the Heresy dragged on to the lower levels of the Hives. Within 3 generations of the end of the Horus Heresy, over 80 percent of the Hives belonged to the 'Church of the Sacred Word' as it was called, led by the newly emergent Priest-Kings.