Editing MidHammer 40,000: SM Chapters (section)

===Creation of The Codex Astartes ===
The first writings that would eventually become the Codex Astartes were composed by Rouboute Gulliman during his last days on Maccragge. Alone in an empty planet, the Thirteenth son began writing down his thoughts about each individual legions, its greatest strengths and its greatest weaknesses. He also mused about the ramifications of "The Great Treachery" (The Lorgar Letdown), and its impact on the Imperium. It was here that he called for legions to be broken up into individual chapters, with the remaining Primarchs leading their sons by example rather than by force. This he argued, would not only ensure that further treacheries would not happen again, but allow the Astartes to redeem themselves to the greater Imperium.
 
The break up of the chapters, [[MidHammer_40,000_drafts#Codex_Astartes_2|in Gulliman's mind]], was needed to correct the rising indifference he noticed in both his and other legions. By shifting the Astartes as protectors of individual planets, they would begin to see the imperium for its citizens and culture rather than as an abstract notion.
The Collected writings of the Codex were smuggled out of Maccragge by Nathaniel Garro, who along with other loyalists was betrayed by Mortarion and Kor Phaeron. Roboute Gulliman died in Kor Phaeron's ritual, in which Maccragge was consecrated to the dark gods and the corpses of the multitude of dead heros were possessed by the demons of the Ruinous powers. These beings eventually tortured and killed Roboute, but not before he helped Nathaniel Garro and the remaining Loyalist Death Gaurd and Word Bearers to escape.
The Codex Astartes was compiled and authored by Jaghatai Khan (the nomad prince), who took on the notes and writings of his friend Roboute Gulliman (the institutionalist) as a way to preserve the relations between Ultramar and the Greater Imperium. The realm of Ultramar was still spiritually and physically scarred by the Scouring of Maccragge and the Primarch treachery. Between bearing the brunt of the LL, and the misinformation campaigns of Alpharius (claiming that The Imperium ordered Gulliman killed and maccragge destroyed), Ultramar was suspicious of returning to the Greater Imperium at large. Khan, feeling guilty about the death of his friend, and how his Legion was spared most of the losses that befell his brothers, saw this as a way to make amends. Because the book was co-written, Rouboute's concerns about legions going traitor are tempered by Khan's nomadic experience with settler decadence and horde fragmentation. The result is a pseudo-united "Paralegionary" Force. The Khan willingly cedes control of two thirds of his Legion to be broken up into chapters, and the now Rogue Ultramarines agree to do the same. These Chapters are scattered throughout the galaxy. They can come at the request of The Primarchs (or other Imperial or Ultramar governors), but they ultimately answer to no one but The Emperor. Certain Primarchs (Magnus, Fulgrim, Corax, Vulcan) could have these Free Chapters help shore up the dwindling defenses of their territories. It also gives the Emperor a little bit more direct control over regions, (cant be too careful...). Eventually Primarchs like Rogal could grudgingly see the wisdom in this and donate chapters to fortify around the eye of terror. One of Khan's Stormseer successor chapters eventually becomes "The Grey Knights," etc. Perhaps too other Primarchs allow for some of their sons to form chapters according to the Khan-Gulliman Codex. The Blood Ravens could be an example of one such. Additionally, since both RG and JK have the most stable Geneseed (besides Rogal), and other legions would be disproportionately affected by the "Lorgar Letdown," the splitting of these two chapters would be seen less as a break up, and more of a "flowering" since the Khan would expect their successor chapters to act like Nomadic Bands that split off to form their own vibrant tribe. While Gulliman and Khan are technically no longer incharge of any of their now emancipated sons, they still have significant authority over The Codex itself, and any changes and revisions made.