Most Important Documents in the Imperium

 Most Important Documents in the Imperium of Man

As one would expect of a galaxy spanning empire with more than ten-thousand years of accumulated history the Imperium of man has generated a LOT of written records over the millennia. Most are relatively insignificant but some have come to hold near mythical status. 

The Codex Astartes

Easily the most iconic and well-known document in the Imperium the Codex Astartes actually represents a vast repository of tactical knowledge and doctrine that has been edited, added to, revised and re-organized countless times over the last ten thousand years. The original tome written by the Primarch Roboute Guilliman was a momentous document that split the loyalist legions into the modern chapters, reducing the standing strength of individual space marine armies from tens of thousands to no more than one thousand and also laid out a unified doctrine for organization and equipment of these chapters. However the original work could never have reflected every enemy or every tactical situation the space marine chapters have encountered in the ten thousand years since the primarch's fall. The Tyranids, Tau, Necrons, Ynnari and many more foes did not exist in the time of the primarchs and many chapters, even the most dogmatic, have had to add their own experiences and insights to the pages of the codex over the centuries. The oldest remaining copy of the Codex Astartes is known as the Apocrypha of Skaros but even this legendary copy of the work is not an original edition nor is it a complete work. For instance the Apocrypha of Skaros states that twenty-three successor chapters were formed from the Ultramarines legion but it fails to list these chapters. Perhaps such information was originally recorded in another section of the tome that has since been lost to time. 

With the introduction of the Primaris Marines and the return of Roboute Guilliman the primarch of the Ultramarines has taken upon himself the task of writing a new revised version of his great work, a tome that includes a wide range of alterations to the organization and structure of codex chapters. Some of these alterations include the provision for seconded support squads to be included in the structure of battle companies including squad numbers up to and beyond twenty where ten was the previous limit, this includes the provision for squads below ten men in strength reflecting the three man units commonly seen in specialist squads of the primaris marines. The final form of this work has yet to be seen but when it does it will surely represent one of the greatest changes to the doctrines of the space marine chapters in the history of the Imperium. 

Lex Imperialis

The Lex Imperialis is the collective name for the general galactic laws that govern the Imperium. With over a million worlds in the Imperium each one with it's own government and local laws, law enforcement and customs the grand law of the Imperium cannot possibly reflect the unique variations seen across the Imperium's worlds. Instead the lex reflects the laws that govern all worlds of the Imperium and is enforced by the will of the Adeptus Arbites, the brutal arbitrators who ensure the rule of Terra is obeyed and the Imperial tithe is collected. Regardless of local laws or customs the word of an Arbitrator is law, superseding even the will of appointed Imperial Governors in matters that effect the wider Imperium. Many systems may fall under the remit of a single arbitrator who may oversee the local lex enforcers of multiple worlds while the most populous and strategically vital Imperial worlds, often Hive or fortress worlds, will possess multiple arbites precincts housing hundreds of arbitrators of a wide array of different ranks and specializations. While the arbites represent the unflinching will of the Lex Imperialis across the wider Imperium the ultimate authority of Imperial law falls with the Adeptus Custodes, the Emperor's personal guards. Custodians carry ritual daggers called the Misericordia, weapons of execution that represent their ultimate authority over the lex, permitting the wielder to stand judgment over anyone up to and including the High Lords for crimes against the Emperor's laws. For most of the last ten thousand years the Custodian guard was restricted to Terra by the Edict of Restraint, a formal policy enacted by the High Lords in the days after the Horus Heresy. Following the return of Roboute Guilliman and his appointment as Lord Commander of the Imperium the edict was withdrawn allowing the Custodian Guard to take part in the Indomitus Crusade and spearhead the Torchbearer fleets bearing the technology of the Primaris Marines to every chapter of the adeptus astartes. In truth the Lex Imperialis meant little in the time of the Great Crusade for the will of the Emperor and the Primarchs often superseded the written words of the lex and the authority of any Imperial institutions. It was in the wake of the Horus Heresy and the gradual death or disappearance of the Primarchs that the lex, and the institutions of Imperial governance, would rise to prominence in the Imperium. With the return of not one but two primarchs there are those in the Imperium and among the high lords who fear the decline of their power and the possibility of these demigods taking control of the Imperium and bending it to their whims as they did in the days of the Great Crusade. Despite Roboute Guilliman's attempts to allay those fears opposition to his command has led to several attempted coups and rebellions among the High Lords and other Imperial institutions. 

Warrants of Trade

Among the oldest and most important documents in the Imperium the Warrants of Trade are ancient writs that establish the unimpeachable rights of the bearers to trade beyond the borders of the Imperium, to engage in commerce with alien species and across otherwise restricted stellar domains, to travel and explore at will and even to raise arms in the expansion of the Imperium and conquest of new worlds. The rights and entitlements of the Rogue Trader houses are protected exclusively by their warrants of trade and to lose such a document means the end of the dynasty. Each warrant of trade was written in the days of the Great Crusade and every single one is signed personally by the Emperor making these documents among the most holy artifacts to the Ecclessiarchy and the Imperium at large, even aside from their importance as legal documents that certify the rights of the Rogue Traders to go where they wish, when they wish and do whatever they wish without restriction or interference. Truly there are few crimes a holder of a warrant of trade can actually commit for these documents empower their holders to engage in all manner of activities that would be considered treasonous or heretical should anyone else dare to do the same. While many thousands of merchant vessels ply the warp routes across the Imperium transporting all manner of goods and materials from one place to another the fleets of the Rogue Traders are not just merchant transports and their commerce and exploration can take them far and wide across the galaxy. Rogue Trader fleets may contain warships fit for the Imperial Navy and transport vast armies of professional or mercenary soldiery retained by a Rogue Trader for the purpose of conquest. Rogue Traders militant can be found at the forefront of many expansionary crusades across the history of the Imperium and whole stellar domains have been claimed in the name of one dynasty or another, their worlds beholden to the dynasty that founded them and their wealth tithed first and foremost to the Rogue Traders even before the Imperium. 

The Sidon Protocols

The Sidon Protocols are not exactly singular documents but rather a collection of oaths and treaties that formalize the allegiance of Imperial Knight households with the Adeptus Mechanicus. Some of these agreements may be contained purely as binharic sermons or as oral traditions memorized and recited by generations of household nobles but regardless of the form these agreements take the Sidon Protocols are binding obligations that almost irrevocably tie noble households to the Martian Priesthood. So absolute is a knight house's bond that when many forge worlds sided with the traitor Kelbor Hal and sided with Horus during his rebellion their bonded Knight Houses fell into heresy with them. Forced by oaths to do unspeakable and dishonorable deeds but compelled to obey the contradiction drove many fallen nobles insane. Most knight houses predate the foundation of the Imperium and those that were sworn to Forge Worlds before their rediscovery during the Great Crusade therefore have Sidon Protocol oaths that predate the Imperium as well. The oldest knight house, House Taranis, existed before the creation of the Standard Template Construct systems and before the mass colonization of the galaxy. The Sidon Protocols binding Taranis to the red planet of Mars stand at somewhere between twenty and twenty-five thousand years old, more than twice the history of the Imperium itself. Precious few other Imperial institutions can claim the history or lineage of the Knight houses and their ancient alliances with the Martian Priesthood. Some Knight houses that undertake the sidon protocols and swear to the service of a Forge World do so out of bitter necessity, their strength all but spent and in desperate need for arms, armor and technology and thus become little better than conscripts in the service of their Martian masters. Other houses are respected partners, powerful and largely independent entities viewed with great reverence and capable of exerting considerable power and influence who joined the Mechanicus more out of a shared view of technology or purpose than necessity. Those houses who may resent their bond with the priests of Mars have little opportunity to sever their ties, only House Cadmus is known to have been freed of their bonds to the Mechanicus. The nobles of House Cadmus were freed when the Forge World of Gryphonne IV, whom they were sworn to, fell to the Tyranids of Hive Fleet Leviathan. The fall of the forge world freed it's vassals from their oaths of bondage and permitted Cadmus, along with a number of other worlds and domains, to reclaim their independence. How the Mechanicus in general will respond to this turn of events or whether reprisals will be enacted against Cadmus or other factions that may attempt to slip their yokes remains to be seen. 

The Lectitio Divinatus

It is a great but little known cosmic irony that the tome that founded the Imperial Cult, the singular religion of the Imperium that venerates the Emperor as the god of all mankind, was penned by the greatest heretic to ever live: Lorgar Aurelian. Before he fell to chaos the Primarch Lorgar was a fervent believer in the divinity of the Emperor and penned the earliest versions of this belief in a tome he titled the Lectitio Divinatus. Roughly translated as the reading of the divine the Lectitio Divinatus proclaimed the Emperor to be a divine being and the unquestionable ruler of mankind, the power that would guide the Imperium into glorious salvation from the many threats of a hostile galaxy. Lorgar's own faith would fail him when the Emperor himself would punish the wayward primarch for his worship and humble his entire legion on the world of Monarchia where the Emperor would order the Ultramarines to raze the cities and cathedrals of the Word Bearers to the ground before their very eyes. Bitter and broken Lorgar would be easy prey for his long patient advisors Kor Phaeron and Erebus, both of whom had secretly preserved the worship of chaos in secret, to corrupt Lorgar and turn him to the worship of the dark gods. These traitors would go on to spread their corruption to many other legions through the secretive warrior lodges and poison the Primarch Horus with the anathema blade, resulting in his fall to chaos and the beginning of the Horus Heresy. Despite the best efforts of the early Imperium and the forces of the traitor to crush the spirit of the Emperor's subjects and deny his divinity the Lectitio Divinatus would survive the loss of it's authors faith and be passed on from hand to hand across the length and breadth of the Imperium. Often copied on scrap paper from crude machines in hidden bolt holes or scribbled by hand the Lectitio Divinatus spread like wildfire in secret, it's worshipers facing harsh reprisal and even summary execution should they be found to possess a copy or extol the divinity of the Emperor. The worship of the Emperor would crystalize around the first Saint, Euphrati Keeler, and the Emperor's Champion Sigismund of the Imperial Fists. Both figures would be instrumental in the defense of Terra during the traitor siege and despite attempts to suppress the worship of the Emperor in the aftermath it would spread to the point that even the High Lords could not deny the growing cult any longer. Over the next few thousands years the worship of the Emperor would become the de-facto religion of the Imperium with thousands of different sub-cults establishing themselves across many worlds of the Imperium. Various heroes and figures would be deified as saints and miracles would be witnessed and recorded. In the modern Imperium the worship of the Emperor is the Imperium's law and only a handful of institutions such as the Mechanicus and some chapters of the Adeptus Astartes dare defy this worship without risk of summary execution for heresy. 

Honorable Mentions 

The Imperial Infantryman's Uplifting Primer and the Imperial Munitorum Manual

-These two documents represent the bulk of the instruction and guidance given to members of the Astra Militarum on tactics and administration. The Uplifting Primer provides a wealth of questionably useful information on combat tactics and the enemies of the Emperor as well as helpful prayers and fieldcraft instruction. The Munitorum Manual provides a wide variety of useful requisition forms and guidelines for maintaining and requesting equipment and supplies from the Munitorum. Both of these documents are widely produced across the Imperium and exist in many hundreds if not thousands of different versions and formats produced for specific worlds or sectors or sometimes even for specific campaigns and warzones. Few others books in the Imperium are so widely produced or circulated as these and in a pinch they at least provide guardsmen with some useful kindling or sanitary wipes when stranded in the field without supplies.  

The Restricted Memoirs of Commissar Ciaphis Cain

-The officially published memoirs of the legendary Hero of the Imperium and celebrated Commissar Ciaphis Cain are stiff and pompous accounts of military campaigns without much heart or candor. The private memoirs published by Inquisitor Amberly Vail are a much more honest and self-critical depiction of the actions and motivations of Commissar Cain throughout his long and illustrious career. Within these memoirs Cain reveals his often selfish motives and his deep-seated imposter syndrome while his inflated reputation drags him from one life-threatening crisis to another that he somehow manages to escape from largely unscathed by seemingly miraculous circumstances or impossible feats of heroism, strategy or skill at arms. That Cain had a long-running romantic relationship with Inquisitor Vail certainly adds to the intrigue of these accounts and in fact these memoirs published exclusively for the eyes of individuals with Inquisitorial clearance have become highly popular entertainment reading for members of the Emperor's most holy Inquisition. Despite Cain's obvious and oft-stated selfish and cowardly motivations his actions often stand in stark contrast to his own stated intentions, often Cain will act in a manner that is genuinely selfless or extremely heroic and his skill with laspistol and chainsword cannot be denied. Although he has certainly never faced a uninjured and battle ready space marine in single combat and prevailed Cain has defeated a number of incredibly lethal foes through a combination of skill, luck and the presence of his warp-nullifying personal aide Gunner Jurgen. These deadly foes include Genestealer Patriachs, chaos space marines, daemon princes of chaos and even an ork warboss in mega armor. Often the simple fact that Ciaphis Cain seeks alternative solutions to problems than simply throwing troops at the enemy and hoping for the best allows him to achieve victories that would have been impossible for more typical Imperial officers. The incredible loyalty and high morale that Cain inspired in the soldiers around him and the great trust and confidence the officers he served with showed in him seem to have largely gone unnoticed by the hero of the Imperium.  

 

Like a Phoenix from the Flames: the Founding of the 597th 

-These memoirs, written by Lady General Jenit Sulla, detail the early campaigns and formation of the Valhallan 597th Regiment and the command of the legendary Commissar Ciaphis Cain. General Sulla would probably have been horrified to learn that Cain held her in absolute contempt and hated almost every second he was in her presence for she almost certainly carried a blazing torch for the commissar and modeled her every action on her ideal vision of the commissar's own heroics. Cain and the officers of the Valhallan 597th typically viewed Sulla as dangerously impetuous, prone to risky maneuvers and ill conceived tactics however Sulla's actions almost always delivered decisive victory. Inspired by Cain the young Sulla rose from Lieutenant to Captain and earned the deep respect and admiration of the soldiers that fought under her for she led from the front in every action, was bold and decisive in her decisions and was fiercely loyal to her troops and allies. These traits would eventually lead Sulla to an illustrious career rising to the rank of Lady General and earning considerable glory and renown on the battlefield. Inquisitor Vail views Sulla's memoirs as an almost unbearable abomination of the gothic language but they are often the only source of contextual evidence for events chronicled in Cain's own private memoirs and so excerpts from Sulla's writing often make their way into the published segments of Cain's own writings. 

 

The War of the Giants

-One of the only written accounts of Space Wolves sagas ever published the War of Giants was written from memories encoded secretly by Inquisitor Bastalek Grim during the Feast of Gerrod Redbeard in the halls of the Fang in 741.M41. The Space Wolves heavily restrict any recording devices or augmetics within their realm and refuse to commit any of their sagas to physical recordings of any kind. This act of recording represents a dire violation of Space Wolves culture and doctrines and was done at great risk by Inquisitor Grim. This violation also most certainly further reinforced the antipathy between the Holy Ordos and the Space Wolves given Grim's presence at this feast was almost certainly an extremely rare olive branch given to an oft hostile Imperial institution. Despite the defiance of fenrisian culture this record represents it is also one of very few, perhaps the only significant, written account of the history and deeds of the Space Wolves and their heroes and thus represents a priceless artifact for Imperial historians. 

 

The Insignium Astartes

-This tome collected the various uniforms, heraldry and organizational markings of a number of codex compliant chapters in the latter years of the forty-first millennium. The standing dictates of the codex astartes to routinely alter iconography and the loss of entire chapters in the later years of the millennium rendered the information in this tome almost immediately obsolete yet it stands as a fascinating record of the uniforms and insignia of a number of chapters at a particular point in time and shows how even among the most strict adherents of the codex astartes there existed wide variety in marking schema and iconography.  

 

The Apocrypha of Skaros

-The oldest surviving copy of the Codex Astartes and thus one of the few reliable records of the early Imperium and the chapters of the Second Founding. This tome lists a full twenty-three successor chapters founded from the Ultramarines Legion though it fails to name all of them.  

 

The Mythos Angelica Mortis

-This tome details the twenty chapters founded to guard the Eye of Terror and defend against incursions into the Imperium by the forces of the traitor legions contained within. 

 

The Catechism Martial

-A detailed tome on combat doctrine written by one of the greatest heroes of the Soul Drinkers chapter, Daenyathos. This tome was the core of the Soul Drinkers combat doctrine and every member of the chapter carried a copy with them at all times. With the Soul Drinkers fall to chaos and excommunication all knowledge of the chapter and all it's works was stricken from history and purged from Imperial archives including all known copies of the Catechism Martial.  

The Chronicles of Ursh

-One of the oldest tomes preserved by the Imperium and widely regarded to be the stuff of fiction the chronicles detail the rise of the pre-Unity empire of Ursh and the warlord Kalagann as well as his wars against the Nordafrik Conclaves. The demons and magics referred to frequently in the chronicles struck the Imperial historians and Remembrancers as outlandish and absurd yet the tome was kept and would become the subject of much more intensive study by Kyril Sindermann who would himself come to be one of the founding members of the Imperial Inquisition.