Great Crusade Logistics

[b1soul]

If I understand correctly, the Imperium did not expand greatly after the Great Crusade. Some world were lost and some were gained on an ongoing basis after the GC.

 

So that would mean the IoM conquered around 1 million planets in a 200 year span, with hundreds of thousands of SM (later between 1 to 2 million SM) and Imperial Army, Navy, Mechanicum, and Knight support.

 

1 million planets over a span of 2 Terran centuries years...is on average 5,000 planets per Terran year...is on average 13 to 14 planets per Terran day

 

I'm assuming quite a few planets were lightly defended or even uninhabited. Others fell perhaps a dozen or so at a time when the capital planets of petty empires surrendered.

 

Do these logistics make sense...if Warp travel time is factored in? Do we have the total number of expeditionary fleets and personnel prosecuting the Crusade (on average roughly...as the number prob fluctuated over time)?

[Stofficus]

Correct me if I'm wrong, but while the Imperium's physical boundaries were more or less established by the end of the Great Crusade, a great deal of that territory wasn't "back filled," and I don't believe there is any claim in the Horus Heresy era publications which state the Imperium is "a million worlds" like is the case in the 41st millenium. 

Ergo, I would expect the M31 Imperium to be more like 10k inhabited worlds, with really only a fraction of those proper, developed, integrated "Imperial" worlds, with most either just agreeing to be part of the Imperium with some basic Imperial trappings, say a small Imperial Army garrison or a trio of grumpy Iron Warriors, and some basic administrative support. After all, the Imperium of M41 still invests heavily in colonization, exploration and expansion - they may have marked on some big fancy maps that "All of this belongs to us," the sheer scale of the galaxy means a lot of that is little more than a boast. 

As for acquisition, you're on the money for petty empires joining the Imperium en-masse - after all, the staple tactic of the Legions was eliminate command and control, especially with "redeemable" human cultures, and a great many worlds breathing a sigh of relief to see they weren't alone and signed up without a shot fired, and once the iterators signed off on "Yup, they're drinking the kool-aid," that expeditionary fleet patted themselves on the backs and moved on without much delay. 

To use a real world example, Alexander the Great didn't conquer the Persian Empire and march into India with early iron age tech by conquering every city or fighting every Persian force - he smashed their proper armies, made, more or less, a bee-line for the capital and then hounded their leadership to destruction - something his successors spent the next ~250 years trying to hellenize and just maintain, unsuccessfully, the boundaries he established. By the time Cleopatra and Mark Antony, uh, "called it quits," thus marking the end of the last of Alexander's successors, that part of the world was firmly hellenized, in spite of the political/military failures of the Macedonian kingdoms, and would remain so for ~1000 years further. It's entirely practical to establish control over a vast territory, and then begin a generational project of nation building from almost nothing, just up the time scale, and general scale, and you have the position of the Imperium of Man. 

[Kite Senet]

I think your initial premise may be incorrect. Even if the rate of conquest per capita slowed to a fraction of the rate before, by the end of the Horus Heresy, the Imperium had a lot of capita and a lot of time to grow. Much of this growth occurred during The Forging, but I would expect that expansion of a more moderate and natural type, akin to planetary-scale urban sprawl, has been expanding the Imperium's boundaries substantially for 10 millennia.

 

Furthermore, much of the Great Crusade's expansion was likely simply planting flags on suitable barren worlds, or simply saying hello to the natives, impressing them with shiny guns and tanks and maybe even the Imperium's shining angels of war, and signing them up for Imperial citizenship. One shouldn't assume all the planets of today were fully developed worlds at the time they were claimed for the Imperium. (Though perhaps that is obvious.)

[Vykes]

Hmm, I seem to remember that the Imperium of man during the Great Crusade was quite a bit smaller than the Imperium of Man of the 41^st Millenium. The number I remember was that it was a height of about 250,000 worlds, and many of them were brought into compliance via negotiation and reunification rather than pacification. Thus, you get places like Ultramar and a number of mechanicus stellar clusters which may have dozens or hundreds of worlds quickly join up with Imperial rearguard elements getting ferried in after for certification that marked the worlds as 'compliant'.  

 

Stofficus is quite right, there's a lot of 'Backfill' that had to happen to get where the Imperium is currently, and even after the Rift opened, the current Imperium is still likely a whole lot larger than the Great Crusade era. I'd also say that a lot of the Great Crusade's efforts were likely easier to work with. Compliant worlds didn't need to be massively pacified, but were just said to be 'compliant', raising the tally, then when governors or the proto munitorum tax collectors came in, they hoped that there wouldn't be too much trouble. The mechanicum was still at its peak, recovering new STC data, new forgeworlds, and Mars may have been in a state of flux due to the various houses and Forges that existed, but they were more unified and lost less equipment lost.  The threat of Titan derived mutually assured destruction kept a balance of power there. Places like Jupiter, Neptune, Saturn, and Pluto had major ship building and forces present which added to the early Great Crusade to add to the momentum and there was not much of a loss of major infrastructure compared to the later Scouring Era (a period where the Imperum sunk back even more with tremendous reprisal attacks, scorched earth, and enormous loss of life and infrastructure).

 

Forges produced more equipment for the Legions, legions had a more unified command structure under the Principia Belicosa to the point that Legionnaires could be recruited from anywhere and were shunted into legions that required new recruits rather than being drawn from gene-specific tithe worlds, and we have recruitment rates which are crazy (with marines being created in a matter of a few years for well drilled Dark Angels, which was eventually shaved down to... what was it, was it 8 or 18 months? I have a hard time recalling the Dark Angels 30K books).But recruitment was faster to replace heavier losses, equipment was being manufactured in massive quantities from well supplied forges that had requisition teams expanding alongside the legion 'conquests' (o hi Caliban), and warp travel was calmer and easier than it had been at any other point in 'recent' history.

 

There was more than 1,000 exploratory fleets (if we take their numeric designations into account) which means that those exploratory fleets, with legion forces hitting hot zones en mass, were able to subjugate about 3.4 planets a day.. which is still pretty ridiculous. There's a lot of things that would be tough, and most of it would be the logistics of being able to supply things like fuel and munitions, so a lot of that had to be taken in faith that forge worlds brought back into the fold would be able to supply them in massive numbers with more efficient and open supply routes. We know in some things that technology took a massive MASSIVE step backwards thanks to the efforts of the Dark Mechanicum (CRT defence monitors... really. Dear Warmaster, really, Only in Duty?) It's not impossible, the Crusade era seems like a wildly optimistic time, 40K is stagnation of Grimdark grim-darkness bureaucracy that wants to waste massive amounts of resources to fuel the dreariness of the far far future.

 

Man, I'm getting long winded, but I think Stofficus is right and even the 250,000 number at the end is more or less a boast in the Imperium's sphere of influence rather than actual tangible control. Plus, it's hard to properly 'get' how important the Emperor and Primarchs were as a force of will and charisma in swaying populations that had just emerged from the Dark Ages of Old Night.  The Helinization comparison is immensely apt, even if the socio political climate is even more ripe from the Imperium's standpoint. 

[b1soul]

Yeah, did't know about the forging...I thought the IoM peaked at the end of the GC, and subsequently experienced growth and decline roughly offsetting each other

 

...and yeah, many compliances were "peaceful" surrenders or even diplomatic triumphs

[Laughingman]

Laughingman's theory:  the logistics of the great crusade don't make sense because the lore and background writers are not experts in logistics or statistics... 

[b1soul]

I'm wondering what sensible logistics would look like

[Vykes]

My assumption would be enormous stepping off points (like Beta-Garmon, Vraks, etc) with massive stores cultivated from local systems and siphoned off to warzones or other sub-sector rally points using those massive Universe- class fleet tenders and getting massive merchant fleets in order to provide for them.  Honestly, I can see things like Rogue Traders and other sponsored and chartered private guilds/factions/houses/etc being the only plausible key to providing for the Great Crusade.  On one hand, it can easily pacify systems by saying, "yes, we have a massive military organization, newly discovered space faring world.  We'll pay and you get to stay in control, so long as you say we're in charge and have this clerk in his new apartment, kay?"   Mechanicum and forging plants would require quotas to fulfill which should have them further economize production of select items for the Imperium's conquests, large scale indoctrination and recruitment facilities for inducting military and astartes personnel, more leeway in some practices to ensure local compliance put back behind schedule, thus stalling efforts, and stable warp zones would have to be charted. 

 

Honestly, I think the Great Crusade could well and done all of the above, and been massively punished as it comes down to making all of those large scale requisition filling agencies easy targets in a civil war.  Horus knows the Emperor's forces need fuel, so he targets the massive jupiter-style fuel refineries.  Traitor forces seize control of a major ordo reductor experimentation facility, so Imperialists send in strike teams to touch off the labs to deny Horus the new information.   Thus further punishing future efforts and causing regression. 

[Ryltar Thamior]

To use a real world example, Alexander the Great didn't conquer the Persian Empire and march into India with early iron age tech by conquering every city or fighting every Persian force - he smashed their proper armies, made, more or less, a bee-line for the capital and then hounded their leadership to destruction - something his successors spent the next ~250 years trying to hellenize and just maintain, unsuccessfully, the boundaries he established. By the time Cleopatra and Mark Antony, uh, "called it quits," thus marking the end of the last of Alexander's successors, that part of the world was firmly hellenized, in spite of the political/military failures of the Macedonian kingdoms, and would remain so for ~1000 years further. It's entirely practical to establish control over a vast territory, and then begin a generational project of nation building from almost nothing, just up the time scale, and general scale, and you have the position of the Imperium of Man. 

If memory serves, he then reached the edge of the Astronomican or thereabouts, and died a broken man as a result of his aspirations of spirit being unmatchable by his body and body of men. :P 

 

But yeah uh, particularly with the Macharian Crusade in mind, there seems a reasonable possibility that even into relatively late in Imperial history, substantial numbers and areas of worlds which had not been conquered or oherwise iincorporated during the Great Crusade were being brought into the Imperial fold. 

 

(and in light of what you've said about the 'Hellenization' of that span of Terra lasting for the next thousand years or so ... I do find myself wondering whether, on a relative scale admittedly, this means that Alexander had a rather better and more enduring legacy than Alexander-In-Space :P But that is another story for another time/thread]

[Marshal Rohr]

The scale of the destruction of the Heresy meant a large swath of the Imperium would have very little history or culture left after the conflagration subsided.

[nagashnee]

I am sure the HH books mention the Imperium reaching 2 million worlds by the end of the Crusade. With the 1 million being the number it hold after the heresy/scouring. 

[carlisimo]

The short story Misbegotten (in the Sons of the Emperor anthology) has a line, “But for every world or culture that resisted, or denied the offer of friendship, for every xenos race that baulked and drew arms at the approach of mankind, a hundred worlds rejoiced and hymned their relief to see the expeditionary fleets take high anchor in their skies. The Great Crusade, so called by those who came later, was for the most part bloodless.”

 

On the downside, the story also has the 63rd expeditionary fleet (Horus’s) sitting for 20 months while mustering before Ullanor and obtaining six peaceful compliances in that time.

 

If there were 1,000 expeditionary fleets at the peak, I’ll assume there was an average of 500 during the Great Crusade

 

As for the number of compliances… Stofficus’s 250,000 isn’t bad. We know multiple planets sometimes came into the fold together, like Ultramar, and forge worlds always seemed to control multiple planets too. An average of a few worlds per compliance seems reasonable. I’m not convinced that the Imperium is larger in M41 than right before the Heresy, though. It obviously expanded in places, but planets get wiped out pretty regularly, too. And new colonies established during the Great Crusade tended to be on worlds that had been ‘cleansed’, which means they counted as compliances (e.g. Cadia).

 

So if we’re conservative and say there were 500,000 compliances, and 500 expeditionary fleets, that’s 5 a year per fleet. Horus’s fleet managed 3.6 while sitting still to muster, so 5 while moving seems okay. It probably takes several months to either conquer a world or negotiate terms, but a fleet can cover several places at once. I’d say it works.

[Vykes]

I'm curious on where the million or multi million worlds quote are from (beyond the million worlds spoken about in the prologue, or the millions of worlds lost in Old Night).  Compliances seem like they could be quick.  I just swiftly skimmed and came across a quote from Betrayer that said, "They only had twenty thousand legionaries down there, but when you were dealing with warriors of that calibre, ‘only’ was a relative statement. Several hundred could take a world in months. Several thousand barely needed a week."

 

But the number of worlds was a quote from Angels of Caliban (I'll have to look later if its corroborated) "One moment, we were a world alone in an uncaring galaxy. The next, the latest addition to the Imperium, one of more than a quarter of a million worlds united under the Emperor." contextually I'm fairly certain they're talking about the time of Caliban's compliance, but that's an assumption.  Just saying that's where the number is from. 

[calgar101]

Book 5: Tempest mentions the Imperium being made up of millions of individual worlds.

 

"Though it may seem inconceivable that treachery on such a scale might remain hidden from the galaxy at large, the sheer size and complexity of the Imperium worked to Horus' favour. in those days the Imperium was formed of millions of individual worlds, semi-autonomous realm and treaty bound tributaries.."