Battle of Calth
| The Battle of Calth | |
| Date | 007.M31 |
| Scale | Intrasolar & planetary |
| Theatre | Shadow Crusade |
| Status | Pyrrhic Ultramarines victory |
| Belligerents | |
| Word Bearers | Ultramarines |
| Commanders and Leaders | |
| Kor Phaeron Erebus |
Roboute Guilliman |
| Strength | |
| Entirety of the Legion with Imperial Army support | ~200,000 Legionaries with Imperial Army support |
| Losses | |
| ~50,000 Legionaries, unknown number of Auxilia | 119,422 Legionaries, half a million Auxilia |
| Outcome | |
| Created the Ruinstorm, preventing passage out of the Five Hundred Worlds | |
The Battle of Calth was one of the major battles of the Horus Heresy and the reason for most of the current hatred between the Word Bearers and Ultramarines.