| Horus Heresy | |
|---|---|
| |
| Military conflict | |
| Date | M31 |
| Place | Imperium of Man |
| Result | Phyrric Loyalist victory |
| Combatants | |
 Loyalists
|
 Traitors
|
| Commanders | |
| Emperor of Mankind | Horus |
| Strength | |
| Nine SM Legions, Loyal Imperial army, Loyal Collegia Titanica, Sisters of Silence, Adeptus Custodes |
Nine Chaos SM Legions, Traitor Imperial Army, Dark Mechanicum, Daemons, Lost and the Damned |
| Casualties and losses | |
| Emperor mortally wounded, 2 Primarchs killed, 1000s of Space Marines killed |
Horus killed, 1000s of Space Marines killed |
| Horus Heresy |
| Battle of Isstvan III, Burning of Prospero, Drop Site Massacre, Battle of Calth, Battle of Signus Prime, Battle at the Phall system, Thramas Crusade, Schism of Mars, Battle of Terra |