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40K: The Secret Real Life Origin of Space Marine Chapters

7 Minute Read
Mar 14

Lets talk about where Space Marine Chapters really come from.

Space Marines are one of the most iconic parts of Warhammer 40,000, and few things are as central to the identity of Space Marines as the Chapter. To a Space Marine, Chapter is everything, and the 1000 loyalist chapters were the Imperium’s greatest asset for 10,000 years. For players as well Space Marine Chapters are huge. They define our armies, our paint jobs, and are a huge part of the 40K fluff. Today lets talk about the very real world origin of Space Marine chapters.

Codex Chapters

Since the end of the Horus Heresy the vast majority of Loyalist Chapters have followed the Codex Astartes. Laid out by Guilliman, the Codex sets up the organization of Space Marine chapters. According to the Codex a chapter is divided into 10 Companies, each of a 100 Marines. The 1st Company is the Veteran Company and contains the heaviest troops in the Company. The 2nd-5th Company are battle companies, with a mix of troops. 6th-9th are reserve companies, that though more specialized than the Battle Comapines are still made of the same basic troops types. 10th Company is the Scout Company, featuring the Chapter’s light troops and trainees.

In addition to the 10 Companies the Chapter also has an HQ element, and some support and administrative groups. While Chapters are normally described as being made up of 1000 Marines, doing the math will lead you to find that a full strength chapter would actually have around 1200-1400 Marines, though its doubtful Chapters are often at full size. So where did this organization come from? Where did GW get the idea for the Chapter? To answer that lets look at the distant past of old Earth.

Over the Hills and Far Away

Look familiar? 

The idea of the chapter organization can be pretty clearly traced to the organization of British Infantry battalions in the era of the Napoleonic Wars. During this period, and during the height of the British Empire, the 18th-19th Centuries, the British regular army adhered to a pretty standard formation. The army was divided into Regiments which acted as the largest permanent formations of the military. Each Infantry Regiment was divided into one or more Battalions, which acted as the main building block of British armies.


The Battalion was divided into 10 Companies of troops. Eight Companies, 1-8. were known as battle or center companies and were the regular troops of the Battalion. In addition to these eight companies the Battalion would also contain a Grenadier Company, made of heavy shock troops, and a Light Company, made of light troops who acted as skirmishers and scouts. Ideally each Company was made up of:

– 1 Captain and two Lieutenants or ensigns

– 5 NCOs. 2 sergeants and 3 corporals

– 1 drummer

– 85-100 privates

This would bring each company up to roughly 100 men. In addition to the 10 companies the Battalion would include HQ element, and some support and administrative groups. Ideally a battalion would be about 1000 strong, though this was rarely the case in the field (at Waterloo English battalions averaged about 665 men).

The Sun Never Sets

“I’m far more dashing than Captain Sicarius”


Looking at the organization of the British battalion of the period its very clear that the Space Marine Chapter draws heavily for the organization. In fact the organizations are almost the same, with each being made up of 10 companies of a 100 men, with a heavy and light company book ending the regular troops. Though the Grenadier and Light companies weren’t numbers, and so aren’t the 1st and 10th companies, they were often deployed on opposite ends of the battalion, and when forming column the Grenadier Company always took the 1st place and the light company took 10th. Chapter command also echos the British Battalion which battalions bringing along armorers, chaplains and medical troops.While individual companies don’t match up, British companies were not dived into ten ten man squads, you can see some similarities, as both Company types are often lead by a Captain and two Lieutenants.

The xenos will never break our squares!

Unlike Space Marine Chapters, British Battalions were part of a larger organization, the Regiment. Though Space Marines have no equivalent organization it’s clear they still drew some inspiration from it. British Regiments were made up of 1 or more Battalions, the number varied during wartime, in peace many Regiments only had a signal battalion. Each Regiment was based out of a depot, which acted as the administrative and recruitment center for the Regiment, rather like a Space Marine Fortress Monastery. Many Regiments had either a Depot Battalion or group that remained at the Depot while the other Battalions were in the field. This group would act as a training and recruitment battalion, slowly send batches of new troops out to reinforce the line battalions in the field.  You can see this kind of mirror the idea of the Reserve Companies. You can clearly here see the inspiration for the Chapter.

Other Inspirations?

While the British formations are the clearest inspiration for Chapters they may not be the only. It’s possible American Infantry Regiments, particularly of the American Civil War era also acted as additional reinforcement for the idea. These regiments were also organized into 10 Companies of 100 men each, with a 1000 man ideal straight. This was adopted from the British idea, but did not include any specialist companies. I think the repeated use of this similar formation clearly reinforced the idea that this would be a good thing to base Space Marine Chapters on.

An Obvious Choice

Ahh the 80s…

So why did the founders of 40K pick this formation to base the Chapter on? Well I think it should be pretty obvious. Its arguably the most famous and effective formation in British history, so if a bunch of Brits were going to make their ideal formation it would make sense to pull from their own history. On top of that when 40K was getting started in the 1980 Historical war gaming was huge in the UK, most of the early 40K guys played historical as well. It was even on TV! Both Napoleonic wargames and American Civil War games were very popular and it would have been a organization type they were comfortable with. I doubt you need to look much deeper than that.

The Flaw?

What if the Hun has his own machine guns?

The British Battalion organization made a lot of sense and worked very well in its time period. It doesn’t work as well in a more modern setting. The British army, and others, eventually found that battalions or regiments of 1000 were simply too small for what they needed. Around the time of the 1st World War armies generally started combining battalions and regiments in Divisions, of anywhere between 10-20K. This better allowed the formation to included more types of specialists troops and to absorb the mass casualties of modern war.


Casualties got you down? Better call Cawl!

You can see a similar issue with Space Marine Chapters. As I’ve pointed out chapters don’t make a lot of sense any more. Space Marines have a lot more troops types then the old 5 (terminators, tacticals, assault, devastators and scouts). The old chapter organization doenst work as well when you have dozens of types of specialist troops. Nor are the Chapters really big enough to be in all the places they describe or to absorb the casualties they take (according to the Shadowspear Book the Ultramarine’s lost 100s of Marines scouting the Vigilus system). You can actually see some recognition of this in the fluff as in cases like the Ultramarines and Blood Angels you now have several chapters working together under the Command of Dante or Calgar.

Final Thoughts

Shown: The Final battle of the Ullanor Campaign (maybe…)

The British Battalion structure I’ve described was an ideal one at a particular point in time. There are a lot of variations on it and it constantly change, though I think this is the most iconic and well known.Just like that battalion however there are many slight, or major, variations on the Chapter Organization. Not all chapters follow the Codex. In addition, much like Chapters, battalion and regiments recorded their history and often took on their own character and had rituals and superstitions. I think the match up is pretty clear and the inspiration is obvious. Anyway, hope you’ve enjoyed this quick jaunt into the intersection of 40K and real history. If you like to read more on the subject, is a great basic resource for information on the armies of the Napoleonic Wars. Redcoat: The British Soldier in the Age of Horse and Musket by Richard Holms is a great look at the British army and troops of the time,  With Musket, Cannon And Sword: Battle Tactics Of Napoleon And His Enemies by Brent Nosworthy has some of the best analyses of period tactics I’ve read. If you’re just looking for a good read I’d always recommend the Sharpe books by Berdard Cornwell.

Let us know about your favorite “stolen from history” part of 40K, down in the comments! 

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