854.M30 Discovery of Mortarion - The Primarch Mortarion rebelled against the sorcerous xenos overlords of the toxic Death World of Barbarus, building an army from the suffering people of that poisonous planet. The Emperor comes to Barbarus in his Principia Imperialis fleet and reunites with His lost son Mortarion. Upon meeting the Emperor for the first time, Mortarion was oblivious to any obvious connection or physical resemblance. Angry, Mortarion declared that he and his Death Guard needed no help to finish their quest for justice. The Emperor quietly challenged the stormy young primarch's assertion, pointing out his soldiers' failure to reach the last high citadel of the High Overlord Necare, and then threw down a gauntlet. If Mortarion could defeat the high overlord alone, he would withdraw and leave Barbarus to its own means. But if he failed, the primarch would join His Imperium of Man and Mortarion would swear total fealty and allegiance to the Emperor. Mortarion was true to his oath, and when he failed to overwhelm the last of Barbarus' sorcerous overlords without the intervention of the Emperor, he bent his knee to the stranger and swore himself and the Death Guard to His service. Only then did the Emperor reveal Himself as the young primarch's true father, and the destiny such service would bring: command of the XIV Legion. Shortly thereafter, the Emperor gave his son command of the Dusk Raiders. Mortarion remade them in his own image, renaming them the Death Guard. However, Mortarion never forgave the Emperor for supposedly denying him his vengeance -- and his chance to prove that he was truly better than his foster father Necare.
ca. Mid-800s.M30 Conquest of Galaspar - This was the first major independent campaign conducted by the newly-dubbed Death Guard after Mortarion took charge of the XIV Legion. The conquest of the non-Compliant Hive World of Galaspar remains one of the most remarkable and brutal victories of the Great Crusade's course through the near reaches of the Segmentum Pacificus. When the Imperial support fleet arrived at the world, they were horrified by the aftermath of the slaughter. The billions of humans "liberated" by the Death Guard were almost childishly eager to accept the Emperor's servants and adopt their ways. In the wake of the conquest of Galaspar, the surrounding cluster of worlds quickly capitulated with terrified speed, all willing to submit to Imperial Compliance under any terms as long as they were spared the reaper's scythe.
ca. 800s.M30 Kajor Compliance - On the world of Kajor the Death Guard Legion encountered a warrior race of humans that had fallen to barbarism. Extensive orbital surveys detected no trace of advanced technology, yet it took the XIV Legion nearly six solar months to bring Kajor to submission. Though the Kajori were savages, armed with little more than blades and crude flintlock carbines, this feral race was able to hold the Death Guard at bay. They were able to do so because they possessed fell psychic powers and unseen allies. In his quieter moments, Mortarion often thought of the Kajor Campaign and shuddered. Mortarion would later recount the tale of this campaign during the Council of Nikaea as one example of many why he took a personal stance against sorcery and the use of psychic abilities.
Mid 800s.M30 Destruction of WAAAGH! Mashogg - In one famous instance, a joint Imperial Compliance campaign was conducted by the Iron Warriors, Space Wolves and White Scars Legions against the vast Greenskin horde known as WAAAGH! Mashogg. Legends record that it was the Primarchs Leman Russ and Jaghatai Khan who routed the Orks of Overdog Mashogg's WAAAGH!, while Perturabo was featured only as the "comrade" who calculated the optimum way to bypass Mashogg's low-orbit defences. This would be considered yet another insult by the Primarch of the Iron Warriors, another reason to fuel his growing resentment of his father the Emperor and many of his brother primarchs.
Mid-800s.M30 Compliance of the Araaki Spiral - This was a joint Imperial Compliance campaign conducted by the Iron Warriors, Imperial Fists, Dark Angels and White Scars Legions in a region of space known as the Araaki Spiral. The Araakites were well-versed in the art of building fortresses, and their strongholds were dug deep around narrow passes, remote hilltops and natural barriers in the landscape. Once again, the Iron Warriors were sent to a resistant star system to conduct brutal siege-warfare against formidable fortress-builders. The Araakites knew their craft well and the campaign to take their world for the Imperium proved both bitter and hostile. It would take many solar years for the IV Legion to regain its former strength from the losses sustained during the drawn-out war of attrition that its Astartes suffered in the Araaki Spiral. In the wake of the inevitable Imperial victory, great works of art and heroic verse were composed, celebrating the courage of the other Space Marine Legions, but nowhere in the reams of poetry and artwork were the grim labours of the Iron Warriors judged worthy of note. Only in a predella to a larger work painted by a notable Imperial artisan were the warriors of the IV Legion displayed; it illustrated a lone Iron Warriors Apothecary removing the gene-seed of a dying Astartes as the flag of the IV Legion's greatest rivals, the Imperial Fists, flew over a captured fortress. Perturabo sought out the artist to procure the piece for himself, only to have it put to the torch once he had done so. If his sons would not be honoured properly, he told the horrified artist, then they would not be a part of a record that glorified another. Afterwards, Rogal Dorn offered a rich commission for the artist to repaint the predella, but the artisan wisely refused.
ca. Mid-800s.M30 The Two Wars of Araneus - The worlds of the Araneus Continuity were a series of planets close to the Sol System which had maintained links to one another due to the existence of a series of ancient Warp Gates of unknown origins. The Continuity was ruled by a caste of Technobility from the world of Araneus Prime at the heart of the network of Warp Gates. After an Imperial squadron accidentally jumped through one of their gates, they were boarded and overwhelmed by cybernetically-grafted warriors. An envoy fleet was sent, and was allowed to return bearing the Continuity's answer to the Emperor's demand of fealty. The Technobility flatly refused to bow to the Emperor, but instead invited Him to join their empire as a tributary. For its response, the Imperium turned to the Imperial Fists. It fell to Hashin Yonnad, Commander of the Imperial Fists' 39th Household (Chapter) of Inwit, to prosecute the war. A full-scale assault was launched, and within two solar months their empire was cut from around them, and finally reduced to just Araneus Prime. But at the moment the Imperium was to claim victory, an unknown menace emerged from one of the Continuity's Warp Gates, and soon six star systems of the Continuity burned. Overwhelmed by the vastly larger enemy force, Yonnad made the hard decision to destroy the Warp Gates, sparing the final system, but costing thousands of Imperial Fists' and billions of humans' lives. Araneus Prime survived, but barely. Now a smoking cinder, the Imperium gave the planet a new name to match the devastation found among its charred ruins -- Necromunda.
ca. Mid-800s.M30 Compliance of 82-17 (Nova Shendak) - Early in the Great Crusade, the War Hounds Legion had found three star systems under the thrall of giant xenos creatures who were both intelligent as well as hateful. Their weapons were filaments, metal feathers that they embedded in themselves to conduct potent bioelectrical energies out of their bodies. The War Hounds proceeded to burn them out of their colony nests and chase them back towards their homeworld. But on their cradle-world of Nova Shendak, the XII Legion had, to their immense surprise, discovered humans. The War Hounds, alongside their fellow Legiones Astartes, the Iron Warriors, and a large contingent of Imperial Army soldiers, were charged with exterminating the worms and liberating the humans of Nova Shendak. When the worms finally emerged from the earth to assault their attackers, they met the Emperor and His War Hounds. Though the casualties were horrendous, the War Hounds eventually emerged triumphant and the worms of Nova Shendak found only extinction. The people of that world inherited the planet and became fervent supporters of the Imperium.
857.M30 Discovery of Lorgar Aurelian - Lorgar Aurelian, archpriest of the theocratic Covenant of Colchis, met the arrival of the Emperor with great ceremony, believing him to be the saviour and long-awaited god of the Colchisian faith that he had spread across that world. Despite his insistence to the contrary to his father, the primarch preaches the Emperor's divinity across the galaxy at the head of the XVII Legion. He reshapes the XVII Legion, once called the Imperial Heralds, in his image, and renames them the Word Bearers. Lorgar at this time is considered one of the weaker primarchs by his brothers, largely because of his odd devotion to religion, something specifically prohibited by the atheistic Imperial Truth.
858.M30 Purging of Arachiana - The Word Bearers, newly reunited with their primarch, are tasked with the destruction of the Cult of the Iconoclast on the world of Arachiana; a religion worshipping the "One True God," a being described in the same terms as, but darkly distinct from the Emperor. The tenets of this religion would be incorporated into an early version of the Book of Lorgar.