Editing Space Marine Chapter (section)

== Origin ==

Each Chapter is descended, in one way or another, from the twenty original Space Marine Legions founded to wage the [[Great Crusade]] -- in fact, the term "Chapter" began as one of several names for a roughly thousand-strong division of Marines, as a thousand Marines was few enough to be logistically manageable while numerous enough to handle almost any situation, especially with the assistance of their [[Imperial Guard|Imperial Army]] regiments. However, some Legions preferred to operate at full strength all the time, especially the Sons of Horus (judging from the books, the ''Vengeful Spirit'' housed the Legion's whole first ten companies) and the Death Guard (operating most of the time as a single force of ~90k+ marines). It says something about the sheer manpower of these armies that large portions of the Legion were often benched during a campaign.

The [[Horus Heresy]] proved that having a quarter of a million Marines and billions of Guardsmen under the command of one corruptible individual was too dangerous, so [[Roboute Guilliman]] (''who also originally had a quarter of a million of Marines and millions of Guardsmen under his command''), with the grudging assistance of the surviving loyalist [[Primarch]]s, instituted the [[Codex Astartes]] reforms, where the remaining loyalist Legions were divided into Chapters of no more than a thousand Marines. This event was known as the [[Second Founding]], with the creation of the twenty original Legions being retroactively designated the [[First Founding]]. Which would be a kind of gaslighting to the Marines since both the [[Imperial Navy|Navy]] and [[Imperial Guard]] can match the power of a Chapter with numbers alone. But the Marines are really able to be a real threat to the Imperium, specially if several Chapters unite, as conflicts like the [[Badab War]] has proven. That's why accusations of "Legion building" are taken so seriously.