This Forge World has had a troubled and turbulent history throughout its existence. In the early years of the 31st Millennium, Estaban III declared for the cause of the Warmaster Horus and sided with the Traitors, but at some point, the Forge World was later reclaimed by the Imperium and continues to remain a loyal and productive world.
Much of the early history of Estaban III is unknown, but presumably it was discovered and colonised sometime during the Age of Strife like the other Forge Worlds of the Mechanicum and managed to survive the horrors of Old Night unscathed. Following the dissolution of the great Warp Storms that plagued the galaxy for millennia at that time and the successful campaigns of the Unification Wars, the Emperor of Mankind came to Mars and forged an alliance between the Mechanicum and the burgeoning Imperium of Man with the Treaty of Mars. With this pact sealed, the Battle Titans of the Legio Tempestus took their place in the glorious hosts of Mankind's all-conquering armies during the Great Crusade.
After a campaign of six solar decades at the forefront of the Great Crusade, the Legio Tempestus had suffered heavy losses and needed time to regroup and rearm or risk destruction. Having claimed warden right over key worlds in the Estaban and Orestes Systems, the Legion's master returned to Mars with those of his Legion's God-engines in most need of repair and refit, entrusting command of the remainder of a reorganised demi-Legio to his lieutenant, Princeps Maximus Karania.
Unknown to most outsiders, Karania was a disciple of a certain strand of esoteric machine lore called Teleologicalica, itself a form of arcane numerology, a discipline that purported to predict imminent and all-consuming doom by reference to the patterns of past cataclysms. Perhaps these beliefs might have had little impression were it not for prevailing attitudes amongst the Tech-priests of Estaban III, the Mechanicum domain where the Legion was mustered at the conclusion of the Epsiloid Binary Cluster campaign.
The Tech-priests of Estaban III had not accepted the prevailing Mechanicum doctrine that the Emperor was one and the same with the divine being they referred to as the Omnissiah, and paid only lip-service to the Martian Doctrines. Thus began a chain of events that would lead to a growing rift, more a development of circumstance and distance than any actual acrimony or malice, between the two halves of the Legio Tempestus.
During the galaxy-spanning civil war known as the Horus Heresy, the Chaos-corrupted Warmaster Horus Lupercal courted and indeed caused the corruption of much of the Martian Mechanicum and the Fabricator-General himself, initiating the Martian civil war known as the Schism of Mars. Through this dark alliance Horus brought many Forge Worlds, Titan Legions and Magi into his sway, and also courted a number of Forge Worlds and Archmagi to whom Mars was at best an unwanted and distant authority. This was the case with both Estaban III and Sarum, both Forge Worlds whose loyalty to his cause secured for Horus lines of supply which did not depend on the writ of Mars.
Following the events of the Horus Heresy, Estaban III was eventually scoured of Hereteks and Traitor sympathisers and eventually brought back into the Imperial fold. Oddly, there were persistent stories and evidence long since suppressed of midnight-clad warriors in defaced Night Lords heraldry who savagely attacked Traitor forces during the Loyalist liberation of Estaban III. Whether these Legionaries were merely turncoats or, as some have whispered, perhaps still remained loyal to the Emperor despite their parent Legion having turned Traitor, none can say for certain. The liberation of Estaban III most likely occurred during the time of the Great Scouring. Since that bygone era, Estaban III has remained a loyal and productive Forge World of the Imperium.
An Alliance Re-Forged
When Estaban III was invaded by the myriad Forces of Chaos following the birth of the Great Rift at some point in the early 42nd Millennium, it was the stoic and unforgiving Iron Hands Chapter who responded and stood beside the war-engines of the Legio Tempestus in the Forge World's defence.
- Codex Adeptus Astartes - Space Marines (8th Edition), pg. 56
- Codex: Adeptus Mechanicus (8th Edition), "Bastions of the Machine God," pg. 12
- Codex: Space Marines (6th Edition), pg. 70
- Codex: Adeptus Mechanicus - Skitarii (7th Edition), "Bastions of the Machine God," pg. 18
- Deathwatch: Honour the Chapter (RPG), pg. 35
- Imperial Armour Volume One - Imperial Guard & Imperial Navy, pg. 8
- The Horus Heresy - Book Four: Conquest (Forge World Series) by Alan Bligh, pp. 19, 40, 138-141
- Warhammer 40,000: Rulebook (6th Edition), pg. 193