A map of the early Imperium at the time of the Isstvan III Atrocity in 005.M31; the Isstvan System is located in the far galactic north beyond the boundaries of the Segmentum Obscurus.
The Isstvan System, also spelled Istvaan System in older Imperial records, is a relatively unpopulated Imperial star system proximal to the Segmentum Obscurus. It is most infamous in Imperial history as the system where the first major battles of the Horus Heresy were fought early in the 31st Millennium, including the Isstvan III Atrocity and the Drop Site Massacre of Isstvan V. The system is now all but abandoned, but at the time of the Great Crusade, Isstvan III was a Civilised World and home to 8 billion Imperial citizens.
History[]
Isstvan III Atrocity[]
Isstvan III, also spelled as Istvaan III in Imperial records, was an Imperial Civilised World.
Its population of more than 8 billion people was destroyed by a virus-bombing ordered by the Warmaster Horus during a major deployment of Space Marine Legion forces at the end of the Great Crusade in 005.M31 at the Battle of Istvaan III. This action had been ordered by Horus against his own Astartes troops deployed to the surface of Isstvan III.
The internecine battle that followed between the Sons of Horus, Emperor's Children, World Eaters and Death Guard Traitor Legions and their own Loyalist elements within the ruins of the planetary capital Khry Vanak (translated as the "Choral City" into Imperial Low Gothic) was the first overt sign of Horus' turn to Chaos, and the first battle of the Horus Heresy.
Isstvan V Drop Site Massacre[]
Isstvan V, also spelled as Istvaan V in Imperial records, was the barren Dead World covered in xenos ruins in the Isstvan System where the infamous Drop Site Massacre of the Horus Heresy took place in ca. 006.M31 that deeply damaged the Loyalist Space Marine Legions in the worst betrayal in Imperial history.
During the massacre, the Traitor Legions of the Warmaster Horus redeployed following the virus-bombing of the Traitor Legions' own Loyalist members at Istvaan III at the start of the Horus Heresy during the Battle of Isstvan III.
Upon learning of the terrible atrocity Horus had committed from the survivors of the frigate Eisenstein, Rogal Dorn, the Praetorian of Terra, ordered seven Loyalist Legions of Space Marines deployed under the Emperor's authority to the Isstvan System to bring Horus to account for his actions.
The Iron Hands, Salamanders and Raven Guard made up the first wave of the attack, and were making significant progress against Horus' maddened Chaos Space Marines.
Then the Loyalist reserves were called in to finish the job, but the four supposedly loyal Space Marine Legions comprising those reserves -- the Iron Warriors, the Alpha Legion, the Word Bearers and the Night Lords -- had also secretly betrayed the Emperor and were prepared to swear themselves to the service of the Warmaster and Chaos.
The three Loyalist Legions were almost annihilated in the resulting crossfire from the eight revealed Traitor Legions but several thousand survivors from each of these so-called "Shattered Legions" managed to escape off-world, though they were too decimated to play much more than a supporting role and conduct behind-the-lines guerilla strikes in the defence of the Imperium from Horus' Traitors.
Notable Planets[]
One of the final reports provided to the Divisio Militaris of the early Imperium in 002.006.M31, just before the Drop Site Massacre, indicated that the Isstvan System comprised the following elements and their conditions:
- Isstvan I - Pre-Compliance Human mining outpost; tithe exempt.
- Isstvan II - Gas giant; primary satellite host to lower order autochthonic anomalies.
- Isstvan III - Mortis Terribelum; wreckage field in orbit; Status Unknown; Ad Temperesta augur mission in progress.
- Isstvan IV - Secondary system augury node; Therion Fleet auxillia, tracking lock terminated.
- Isstvan V - Target Prioris; Legiones Astartes Execution Fleet inbound; Status Unknown; Ad Temperesta augur mission in progress.
- Isstvan VI - Gas giant. Primary satellite host to pre-Compliance outpost, 34 minor satellites pending survey.
- Isstvan VII - Xenos structures detected; surface survey pending.
- Isstvan VIII - Dwarf planet; host to pre-Compliance outcast Human elements. Suppression operation pending.
- Isstvan Asteroid Range - Remnants of planetary cataclysm; Cross-Reference: extinct autochthon xenos/ruins on Isstvan I and V. Some evidence of pre-Compliance Human outcast activity.
- Isstvan Extremis - Augury network nexus; silenced by Legiones Astartes action prior to Isstvan III Atrocity.
Sources[]
- The First Heretic (Novel) by Aaron Dembski-Bowden, Ch. 24
- The Horus Heresy Book One: Betrayal (Forge World Series) by Alan Bligh, pp. 38-59
- The Horus Heresy Book Two: Massacre (Forge World Series) by Alan Bligh, pp. 24-25