Changes

|The [[Devastation of Baal]] - [[Hive Fleet Leviathan]] invades Baal, homeworld of the [[Blood Angels]] Chapter. [[Guilliman]] and the [[Indomitus Crusade]] arrive at the end of the battle to aid the Blood Angels and their successors. Afterwards, Guilliman appoints [[Dante]] as [[Regent]] of [[Imperium Nihilus]].{{Fn|4112b}}

|''[[In Blackest Night: The Millennial Wars Appraised]]'' by [[In Blackest Night: The Millennial Wars Appraised|Ayjaepi Clothier]] is published. It is later used by [[Amberley Vail]] as an extract within the ''[[Cain Archive]]''.{{Fn|29a}}

|By logical necessity, this would also be the earliest date that [[Amberly Amberley Vail]] could have written the Memoirs of [[Ciaphas Cain]], at least those pertaining to [[Cain's Last Stand]]. This would be, by her reckoning, at least 125 years after the events of the [[Second Siege of Perlia]] and the [[13th Black Crusade]].{{Fn|29d}}

*It is feasible that, given the secretive nature of the [[Inquisition]], the doubt as to whether or not the Indomitus Crusade takes place in M42 or M41 is knowledge that is limited to the [[Ordo Chronos]] and [[Roboute Guilliman]], and that the Galaxy at large simply moves on as if it were M42.{{fn|16c}} This would explain how other historians and even Inquisitors such as [[Amberly Amberley Vail]] would date events that occur during and after the 13th Black Crusade as M42.

*Even Inquisitors themselves are not always adequately informed about galactic events at large. In [[Kill Team (Novel)]], [[T'au]] envoys are surprised when [[Inquisitor]] [[Oriel]] expresses that he and his retinue have no knowledge of the [[Damocles Crusade]].{{fn|48}} AmberlyAmberley, despite being an Inquisitor herself, may not be awares of the Chronostrife.

*^{''[[In Blackest Night: The Millennial Wars Appraised]]'' by [[In Blackest Night: The Millennial Wars Appraised|Ayjaepi Clothier]] in 127.M42{{Fn|29a}}}

Given that Cain was also alive to fight the Second Siege of Perlia in the early years of M42, it would also, logically, lead to the reasonable assumption that his burial as referenced by AmberlyAmberley{{Fn|44}} would also have occurred in M42. Similarly, in order to reference ''In Blackest Night: The Millennial Wars Appraised'' in her writings, Amberly Amberley herself would need to be alive as of the year 127.M42 at least.{{Fn|29a}}

For an out-of-character example, narrative events have also been hosted by [[Games Workshop]] subsidiaries, such as [[Operation Storm Falcon]] by Games Workshop Germany as explicitly taking 26 years after M42 and [[The Jollis Raid]] (which occured "at the end of the 41st MilleniumMillennium".{{fn|45}}{{Fn|51}}{{GW-DEE}}

[[imageImage:Calgar Timeline Warhammer 40,000 Character Encyclopedia pg15.png|thumb|250px|<sup>A timeline of some major battles involving [[Marneus Calgar]]. Note that the [[Ultramar Campaign|Siege of Ultramar]] explicitly takes place in 999.M41.{{Fn|49}}]]

However, GW has also introduced the notion of doubt as to whether the events of the [[Era Indomitus]] truly are the 42nd Millennium or not. The emergence of the [[Great Rift]] has caused uneven temporal shifts across the galaxy, with time itself being affected.{{fn|46}} Twelve years after the start of the [[Indomitus Crusade]]{{fn|16d}}^{[[M42#Trivia|[See Trivia]]]} the [[Primarch]] [[Roboute Guilliman]] made an attempt to determine the true date based upon the [[Imperial Dating System]] as laid out by the [[Emperor]] during the [[Great Crusade]]. This was, he notes, made ever difficult by over 10 millenia millennia worth of both dogmatic adherence and thoughtless revisionism, as well as various rivaling rivalling dating systems which had evolved from the original Calendar, which made a true chronicle of the galaxy almost impossible to construct. To his consternation, he calculated that year to be "anywhere between early M41 and a millenium millennium later." It would be the contentious issue of the Imperial date over which the [[Ordo Chronos]] would wage the internal [[Chronostrife]] amongst itself.{{fn|16c}}

Certain battles that have confirmedly taken place post Great Rift, such as the 2025 [[Grand Narrative]] battle for [[Mordian]], which would include forces of the resurgent [[Leagues of Votann]] and also of [[Primaris Marines]], are described by Games Workshop as "in the 41st MilleniumMillennium."{{fnFn|52}} In the 2017 version of [[Dark Imperium (Novel)]], the time period was explicitly described as the 41st MilleniumMillennium, though this would be changed to "Era Indomitus" in the second edition of the novel.{{fnFn|5341}}

*{{Endn|2}}: [[Of Honour and Iron (Novel)]], Chapters 1 & 2.

*4: [[Codex Supplement: Salamanders (8th Edition)]]:

*5: [[Psychic Awakening: Phoenix Rising]]:

*6: [[Psychic Awakening: Faith and Fury]]:**{{Endn|6a}}: pg.9

*7: [[Psychic Awakening: Blood of Baal]]:

*8: [[Psychic Awakening: Saga of the Beast]]:

*12: [[Warhammer 40,000 8th Edition Rulebook]]:

**{{Endn|12b}}: pgpgs. 52-53

**{{Endn|12d}}: pgs. 154-159 — ''War Zone: Ultramar'', pgs. 154-159 — **{{Endn|12e}}: pgs. 164–165 — ''War Zone: Stygius'', pgs. 164–165**{{Endn|12f}}: pg. 167 — ''Craftworld Iyanden'', pg. 167

*14: [[Codex: Space Marines (8th Edition)]]:

**{{Endn|14b}}:pg. 29 — ''Chronicles of Ultramar'', pg. 29

*{{Endn|16}}: [[Dark Imperium (Novel)]] (e-version){{CME}}

*21: [[For The Emperor (Novel)]],:

*{{Endn|22}}: [[Indomitus (Novel)]], Part 2 - , Chapter 11*{{Endn|23}}: [[Warrior Brood (Novel)]] — [[Kill Squad: A Deathwatch Omnibus]], Chapter 6, pg. 79 and & Epilogue, pgs. 163-165

*{{Endn|26}}: [https://www.warhammer-community.com/2020/12/05/the-warhammer-preview-online-black-library/ Warhammer Community: Warhammer Preview Online: Black Library (posted 12/505/2020] – Interview with Guy Haley ''(last accessed 12/505/2020)''

*{{Endn|28}}: [[Codex: Death Guard (8th Edition)]], pgpgs. 137-138

**{{Endn|29d}}: Footenotes Footnotes at the End of the Book [1] (E-Version)

*{{Endn|34}}: [[War Zone Octarius - Book 2: Critical Mass]] , pgs. 31-33

*{{Endn|37}}: [[Imperium Nihilus: Vigilus Defiant]]. Pgspgs. 11-17

*{{Endn|39}}: [[War Zone Nachmund: Rift War]]. Pgs, pgs. 10-17

*{{Endn|41}}: [[Warhammer 40,000 8th Edition RulebookDark Imperium (Novel)]], pgs. 52–53(2017 Epub Version) {{CME}}

*{{Endn|43}}: [[Archmagos (Novel)]] - chapter , Chapter 30*{{Endn|44}}: [[Death or Glory (Novel)]] Footenotes (E-Version), Footnotes at the End of the Book [81] (E-Version)

*{{Endn|46}}: [https://web.archive.org/web/20181122134527/https://www.warhammer-community.com/2017/05/04/new-warhammer-40000-the-great-riftgw-homepage-post-4/?utm_source=WarhammerCommunity&utm_medium=Post&utm_content=New40kDarkImperiumMay16 Warhammer Community: New Warhammer 40,000: The Great Rift (Posted 04/05/2017)] ''(archived from [https://www.warhammer-community.com/2017/05/04/new-warhammer-40000-the-great-riftgw-homepage-post-4/?utm_source=WarhammerCommunity&utm_medium=Post&utm_content=New40kDarkImperiumMay16 the original] 22 November 2018, last accessed 17 December 2025)'' - see [[Great Rift/Sources]] in case of dead-link*{{Endn|47}}: [https://www.warhammer-community.com/2020/12/05/the-warhammer-preview-online-black-library/ The Warhammer Preview Online: Black Library (posted 12/505/2020)] - Interview with Guy Haley ''(last accessed 12/17/December 2025)''

*{{Endn|50}}: [[Dominion Genesis (Novel)]]{{CME}}*{{Endn|51}}: [[lex_de_wh40k:White Dwarf, deutsch, 125|White Dwarf 125 (DE)]] , pg.89{{GW-DEE}}*{{Endn|52}}: [https://archive.ph/z80PJ Warhammer Community: Grand Narrative 2025 - Field Commander's Brief] ''Archived (archived from [https://warhammerworld.warhammer-community.com/wp-content/uploads/sites/15/2025/05/upYg7MygY7pTbU2b.pdf the original] 13 March 13, 2026, last accessed 13 March 13, 2026)''*{{Endn|53}}: [[Dark Imperium (Novel)]] (2017 Epub Version)