A century on from his rebirth, Guilliman had not yet grasped all the events of the ten millennia since he fell. Belisarius Cawl had provided the primarch with painful but necessary machine-moderated engrammatic updates, but Cawl was a secretive creature, detached from the wider galaxy while he pursued his quest to create the Primaris Space Marines. His records were incomplete, sometimes highly fragmentary, and all of them were short on detail.

Once again, Guilliman had found his own efforts were required to make up for the shortcomings of others.

The discipline of history, like so much else based on reason, had fallen foul of superstition, fanaticism and the High Lords of Terra’s need for iron control. Comparative and corroborative analytical techniques had given way to the recording of gossip, hearsay and folklore. All was liberally mixed with works of complete fabrication. Imperial interference in redacting chronicles, misguidedly or not, had further destroyed much of the past. War had eradicated the histories of entire worlds. Much knowledge had been burned by zealous inquisitors, often in order to suppress a single uncomfortable truth. If anything, the state of man’s knowledge was worse than it was back after the Unification Wars, when the Emperor had unified Terra before the Great Crusade. Much of Terra’s ancient history, painstakingly pieced together by the remembrancers of Guilliman’s own era, had been lost again.

Knowledge of the warp’s true nature had been suppressed, but patchily so. The great deception the Emperor had practised had become impossible to sustain, though that had not stopped the Inquisition from trying. Knowledge of daemons or the Dark Gods was forbidden. Many innocents had paid the ultimate price for accidentally learning the truth.

Even Guilliman, the Imperial Regent himself, faced opposition from the Inquisition in his quest for knowledge. To oppose their puritanical redactionism, he had trained his own corps of historitors. Between campaigns, he sought out inquisitive minds, exactly the sort that had long been frowned upon, rescuing them from penal servitude and impending brain wipe. The first handful he had tutored himself, when time allowed. They in turn taught more, and more still. Each one was assessed by the primarch personally. Those that passed were given the rank of historitor-investigatus. Those that failed to meet his exacting standards were given less taxing roles within the new organisation, as librarians, servants and assistants. From his reading, Guilliman had learnt that the brutal machinery of Imperial government was unkind to failures, yet another thing that saddened him about the present age. The primarch had enough blood upon his conscience, and a much finer grasp of how to get the most out of his subjects. No life was wasted.