The Council of Terra was the ancient ruling body of the Imperium of Man convened by the Emperor of Mankind to replace the Imperial War Council after its dissolution in the early 31st Millennium, shortly before the beginning of the Horus Heresy. The Council was a civilian body without Primarch participation, and would become the precursor to the Senatorum Imperialis. The disbanding of the War Council in favour of the Council of Terra was one of the grievances that led several of the Primarchs to grow disenchanted with their father, the Emperor, a grievance that would be exploited by Horus and the agents of the Chaos Gods to gain their allegiance in his attempt to overthrow the Emperor's rule. The Council of Terra was eventually replaced by the Senatorum Imperialis of the High Lords of Terra after the Primarch Roboute Guilliman began the Imperial Reformation in the wake of the Horus Heresy in the early 31st Millennium.
Following the successful conclusion of the Unification Wars in circa 800.M30, the Emperor convened the ruling body known as the War Council to manage the execution of the Great Crusade to reunite the entire human-settled galaxy under a single government. The War Council effectively became the true ruling body of the Imperium during the early and middle years of the Great Crusade. The Emperor Himself sat at the head of the Council; at his left hand was Malcador the Sigillite, perhaps the Emperor's greatest ally during the Wars of Unity and a psyker whose powers were matched only by those of the Emperor. The rest of the Council was composed of talented administrators drawn from the great ruling aristocratic dynasties of Terra and the Segmentum Solar, and when the Emperor forged his alliance with the Mechanicum of Mars in the Treaty of Mars, the Fabricator-General of the Mechanicus also claimed his seat. The War Council was also attended by the Paternova of the Navigator Houses. As the Emperor left the homeworld of Mankind to lead the Great Crusade into the stars, he left the legendary Malcador to act as the Regent of Terra in his stead.
As the Great Crusade progressed, the War Council grew, as an inevitably widening vortex of admirals and commanders, generals, sector governors and ministers of state were appended to its administrative apparatus. Below these luminaries were advocates and technocrats responsible for the Imperial control of far-flung administrative systems and world-regimes with chains of supply and distribution whose scale beggared belief. As the years became decades, each of the Primarchs were discovered and brought into the Imperial fold and were given a seat on the Council, as was the Chief Custodian and Captain-General of the Legio Custodes, the Emperor's bodyguard. Yet, such men were creatures of war and not politics, and as some of the purely human Council members died in battle, or through simple old age or infirmity, they were replaced only irregularly.
After the decisive victory during the Ullanor Crusade, when Mankind's re-ascension to predominance in the galaxy was no longer in doubt, the Emperor bestowed upon the Primarch Horus Lupercal the title of Imperial Warmaster and ceded to him control of all the Imperium's military forces in the Emperor's stead. The other Primarchs were then instructed to follow Horus and obey him and to complete the Great Crusade under his direction. There was, it is said, some disquiet among the Primarchs that the Emperor had decided to no longer fight alongside them, but the Emperor was as adamant as He was close-mouthed as to what He would do on His return to Terra. The Emperor then departed for the homeworld of Mankind and the dungeons deep beneath his great Imperial Palace to begin His great work on the creation of a human extension into the Eldar Webway under a veil of secrecy previously unknown in the Imperium. He drew to him certain advisors and retired to the private vaults of his city-fortress.
Upon his return to Terra, the Emperor called to his side Malcador and the Fabricator-General. He issued them with new commands. No longer were they to support the military campaigns, as these were now safely in the hands of his sons the Primarchs and the newly appointed Warmaster Horus. The Emperor needed time and all of his focus to be directed at his next great project, which would tie the newborn Imperium together and unite it as no other human polity had ever been united. To this end, the Emperor convened the first Council of Terra. Unlike the War Council, of which Horus was now the leader, the Council of Terra would attend to matters of state and the establishment and maintenance of Imperial Law across the myriad worlds of the Imperium. In particular, the Council of Terra was to administrate the establishment of the Imperial Tithe of troops and resources from all the worlds of the Imperium that were required to support the Great Crusade. In effect, under the auspices of the new Council of Terra would fall the entirety of the civil government of the Imperium. Malcador, the Emperor's most trusted advisor, was named as the First Lord of the Council and would lead it in the Emperor's absence. The Fabricator-General of the Mechanicum of Mars, Kelbor-Hal, Chief Custodian Constantin Valdor and the Masters of the Adeptus Astronomica, the Adeptus Astra Telepathica and the Administratum of the Imperium were also appointed to the Council.
Having established the new governing body of the Imperium to carry out the day-to-day work of ruling tens of thousands of worlds and trillions of human beings, the Emperor took refuge in his vast laboratories and workshops beneath the Imperial Palace. He began work in earnest on his new project. While the Emperor was locked away in his subterranean factories, trouble was brewing. The formation of the Council proved to be a contentious decision with the distant Primarchs, who were appalled when news of the formation of the Council of Terra finally reached them on the frontiers of the Great Crusade. Some of the Primarchs took great exception to being ruled by those they deemed less worthy of such an honour than themselves. The less stable Primarchs felt that this was a betrayal of all they had fought and won in the Emperor's name and that their victories now counted for nothing. They, and many of their Astartes, felt that it was they who had suffered and sacrificed the most to build the Imperium and thus it was they who should have the greatest say in how it was ruled, not a council composed of effete Terran nobles and faceless bureaucrats. This was one of many growing resentments that allowed the Ruinous Powers to infect and corrupt several of the Primarchs.
The creation of the Council of Terra, seen in this light, lent new weight to Horus' argument to several of his brothers that the Imperium had been betrayed by their father. He argued that the Emperor had proved more than willing to turn his back on his sons and generals and give power instead to petty mortal administrators and the sycophantic Tech-adepts of Mars who lacked the Primarchs' brilliance and superhuman abilities. As Horus prepared his rebellion against the Emperor, he convinced himself that petty functionaries and administrators had supplanted the Primarchs and the Astartes within the Imperium they had won. Once the Imperium had been wholly geared for the war and conquest that was its life's blood since its inception, but now it had become burdened with parasitic exectors, scribes and scriveners who demanded to know the cost of everything. Bureaucracy was taking over -- red tape, administrators and clerks were replacing the heroes of the age. Horus argued to his more receptive brothers that unless the Imperium learned to change their ways and its direction, its greatness as an empire would soon be a footnote in history books. Horus feared that everything he and his brother Primarchs had achieved would be a distant memory of former glory, lost in the mists of time like the civilisations of ancient Terra. It was this hubris and arrogance that led to the Warmaster's inevitable fall to Chaos and the resultant civil war that would consume the entire galaxy, ushering in a new Age of Darkness that would last for millennia.
Yet Horus and his more resentful brothers had completely misunderstood the Emperor's intent in creating the Council of Terra. The Council was to become the body of civilian government that would administrate the myriad bureaucratic tasks needed for the survival of the newly formed human interstellar empire. The Emperor was determined that in his Imperium power would reside with those men and women who were governed by its apparatus and not with an artificial military elite composed of genetically-engineered beings who were so powerful that they already possessed only a very tenuous grip upon their own humanity. The Primarchs and their Space Marines had been created to give life to the Emperor's dream of a united human Imperium stretching across the galaxy and to defend it from humanity's myriad foes. They were not to rule it as a hereditary caste of immortal warriors imposing their whims upon those they deemed mere "mortals" by brute force.
Tragically, the Emperor's vision of a new Golden Age for Mankind would never be realised due to the machinations of the Dark Gods. Following the calamities of the Horus Heresy and the Emperor's internment within the Golden Throne and the sacrifice of Malcador, the Emperor could no longer take an active hand in ruling His realm directly. The role of Imperial Regent initially fell to Roboute Guilliman, the great Primarch of the Ultramarines Legion. It was he, in the early years of the 31st Millennium after the Great Scouring that followed the Heresy, who set up the new ruling body for the Imperium based on the foundation of the Council of Terra, the Senatorum Imperialis, or as its members were more commonly called, the High Lords of Terra.
Known Members of the Council of Terra
- First Lord of the Council and Regent of Terra: Malcador the Sigillite
- Fabricator-General of the Martian Mechanicum: Kelbor-Hal
- Captain-General and Chief Custodian of the Legio Custodes: Constantin Valdor
- Master of the Adeptus Astra Telepathica
- Master of the Administratum
- Paternoval Envoy of the Navis Nobilite
- Horus Heresy: Collected Visions, pp. 49, 92
- Imperial Armour - The Horus Heresy - Book One: Betrayal, pp. 22-23
- Warhammer 40,000: Rulebook (6th Edition), pg. 403
- False Gods (Novel) by Graham McNeill, pp. 167-168