Timeline

Pre-40.000.000 B.C.E: Data regarding on the details of the War on Heaven is greatly limited. Little information that have survived from that age is available for investigation or has been found to be too corrupted to be used.

20.000.000 B.C.E: A mysterious race known by many as the Vkaeil appears in the galaxy through unknown means of transportation from their home and settle down. Unfortunately for researchers, small amount of data regarding this time period is in either fragments or nonexistent.

18.000.000 B.C.E: The Precursor's spanning empire comes in conflict with the Eldar Empire; it still remains unknown as to what had occurred to instigate hostility between both factions. It is suspected by many researchers that the Eldars viewed them as a foreign threat that needed to be eliminated, thus war erupted with both sides.

5.000.000 B.C.E: The Precursors begin the process of bio-accelerating evolution with selected sentient species in search of a local 'inheritors' to watch over the galaxy (due to data suggesting that the Eldar were bio-engineered by the Old Ones, the Precursors didn't consider them as actual species). The Precursor's population was showing signs of declining and weakening from the warp effects and the war with the Eldars proving costly.

2.780.000 B.C.E: The Forerunner race is the first to be bio-accelerated by the Precursors. Their trail begins.

1.505.000 B.C.E: The Human race and others are soon bio-accelerated by the Precursors. Their trail begins.

630.000 B.C.E: The Forerunners have been deemed a failure because of their little resistance to the warp's effects and plans to dispose them begin. The Precursors begin putting their focus on Humanity and other races that seemed to have a better chance of succeeding the trials and surviving the Ruinous Powers.

629.800 B.C.E: Having foreseen this action beforehand, in a final attempt to destroy the Precursors once and for all, the Eldars secretly tell the Forerunners of their creator's plans for them in hopes of spurring them to wage war and offer an alliance between them.

628.000 B.C.E: Humanity and few other species have been deemed successful at resisting the warp and harnessing it with humans showing better promises than others. The Precursors decide to name humanity and several other species successors of the Mantle.

620.000 B.C.E: In a surprise attack, The Forerunners lashed out to their creators swiftly and without remorse that resulted in countless Precursors lives lost. Then the Eldars came out of their borders to strike at unsuspecting Precursor military forces and claim former Precursor worlds for themselves while the Precursor's forces were trying to organize themselves in the confusion.

609.500 B.C.E: Only few Precursors remain after the attacks. In a last desperate gamble, they turn to the one of Chaos Gods of the Ruinous Powers, Nurgle to save them from destruction. Nurgle agrees with their pleas but asks for their loyalty in return. The Precursors agree to the condition and start transforming.

600.000 B.C.E: The remaining transformed Precursors retreat from the galaxy to one of the satellite galaxies orbiting ours, vowing to return and extract vengeance. The Forerunners and Eldars, believing the Precursors to be dead for good, begin consoling their power throughout the galaxy. Humanity and other species (they had seen the Precursors as fatherly mentors) are outraged by this action and begin to make plans to avenge the Precursors. They form an alliance dubbed the 'Inheritors of the Mantle'.

530.000 B.C.E: The IM begins launching their attacks throughout Forerunner and Eldar space. Many planets are laid to waste by the IM in the first moments of the war.

527.750 B.C.E: Both Forerunners and Eldars start organizing their defenses and send counter-attacks against the IM. The war so far is in stalemate.

456.290 B.C.E: The tide of the war turns in the favor of the Forerunners/Eldar forces. The Eldars had released warp storms into IM regions, thus creating massive damage and losses. That results with entire species being consumed by daemons in the warp because of the strength of their connection to the Immaterium. The IM forces are soon being forced to retreat. The use of the Webway of the mysterious Old Ones gives the Eldar a large advantage over their opponents.

430.000 B.C.E: The Inheritors of the Mantle begins to break down as the war goes badly for them. Some species start to drop out and disappear from existence:

+429.850: the San 'Shyuum retreat to their homeworld, all contact is lost to them shortly.

+428.530: a member referred as the 'Leviathans' evacuate their remaining worlds and retreat to the 'unknown regions' on the other side of the galaxy.

350.000 B.C.E: The alliance is defeated.

330.000 B.C.E: All remaining members that hadn't gone into hiding or weren't outright destroyed are stripped of their empires, technology and exiled to their home worlds.

295.000 B.C.E: The alliance is fully disbanded and their surviving members punished. Peace and order is brought back into the galaxy.

103.000 B.C.E: The Forerunners and Eldars have enjoyed the peace in the galaxy for mega-annums. Unknown to everyone, the transformed Precursors, now calling themselves the 'Flood', begin mobilizing themselves to war.

102.200 B.C.E: Contact with several frontier worlds is lost. They are however, written off as technical errors and only send technicians to fix it. However, those teams fail to report in.

102.000 B.C.E: Without warning, hundreds of worlds are attacked by an unknown race and consumed. The Forerunner and Eldar forces are in disarray and in the process of being destroyed. They soon learn that the unknown race calls itself the 'Flood'.

101.900 B.C.E: While analyzing dead flood forms, scientists are shock that the Flood is in fact, the previously thought dead Precursors and have been mutated beyond recognition and gifted by Nurgle of the Ruinous Powers.

101.700 B.C.E: The Flood continues to invade Forerunner/Eldar space (with the Forerunners taking the brunt of the force) and consume countless worlds.

101.300 B.C.E: The Eldars retreat into the Webway to survive the onslaught of the Flood, thus leaving the Forerunners to fight alone. They start to become desperate on winning the war.

101.270 B.C.E: The Forerunners construct massive shield worlds and ring-like fortresses in hopes of inhabiting them to survive like the Eldar did with the Webway. The Flood however quickly found out and struck and cut off the Forerunner's ancient core worlds from the rest of the galaxy to denied them that chance. All Forerunners throughout the galaxy with the exception of those in the core worlds are consumed.

101.180 B.C.E: With preparations done, the Flood launches an all out invasion on the last remaining Forerunner worlds with all their remaining units. The core world falls one by one until only the original homeworld is left standing.

101.021 B.C.E: Gathering every single unit the Flood has at its disposal, they launch their final attack on the homeworld of the Forerunners and its remaining population.

101.010 B.C.E: In the last act of defiance, the Forerunners detonate their star into a hypernova (it's when a supermassive star explodes in force that makes supernovas of giant stars look pathetic). Thus killing the last remaining Forerunners and wipes out the Flood with it (with a smile on their faces). The consequence of this action, however, results in the birth of a massive black hole that consumes any 'unlucky survivors' that managed to survive the blast and the remains of the homeworld. Thus, the Age of the Forerunners is over, with their proud home system now the resting place of a massive black hole that will be forever known by other races as the 'Eternal Black Gate of Death'.

100.000 B.C.E: The galaxy is once again silent from the end of the war. Without being restricted by the Forerunners and Eldars, many races once again begin to ascend in technology and culture once again.

98.000 B.C.E: The Eldar race leaves the confines of the Webway to find the galaxy different than before. They quickly go forth to reclaim lost planets of theirs and rebuilt their shattered empire while keeping an eye on the other races.

0.961.M2: Humanity launches its first man in space in over two hundred thousand years.

6.2000.M13: The Eldar Empire has gone through a golden age for over one hundred thousand years. Unknown to themselves, their very own enjoyment/pleasure seem to be causing something in the Immaterium but many choose to ignore it. Races like humanity have once again expanded far into the stars and formed their own empires.

6.000.M18: Warnings begin to appear to the Eldar about the disturbance occurring in the warp but many are too caught up in their enjoyment of pleasure to take any notice. Those who do, fearing for the safety of their race, begin leaving the empire to form Maiden worlds or build massive craftworlds to ferry their people.

6.000.M21: By the time the first waves of craftworlds have left the empire, the event known as the Fall occurs. In the Immaterium, the warp churns for a final time before it explodes in a psychic scream that is felt in both the Immaterium and the Materium, signifying the birth of another Chaos God: the Prince of Pleasure, Slaneesh and the creation of the Eye of Terror.

6.000.M21-6.000.M25: The result of the scream creates warp storms of large magnitudes that devastate the galaxy. Killed by their very own hands, Slaneesh consumes (along with most of their gods) the mighty Eldar Empire and most of the race. The other races weren't spared from this destruction; each one lost their empires and their power until they were nothing more than a shadow of their former selves. A massive rift between the Immaterium and Materium consumes the Crone worlds and forms the dreaded warp storm known as the Eye of Terror.

0.000.M25: The Humanity's own empire is in ruins; only the Sol System remains of their once mighty power. Society falls into disarray and later, civil war.

0.000.M25-0.500.M33: The civil war tears the society apart until Terra is the only bastion of Human life left in the system (the warp storms played a part in the mess).

0.500.M33: During the civil war, there have been many leaders who tried to reunite their race together but have always failed without proper support of the people. However, hope it seems appears to be waiting in the future for the Human race.

0.200.M33: Soon, rumors of a mighty leader began to appear around the world. A leader, many said, that is in the process of uniting countries and groups together under one banner referred as the Imperium of Humanity and is referred as the God-Emperor. While there were a few cases where he needed to fight to convince people to join him, most of the time he used skilled diplomacy to convince others to join his cause peacefully. The Imperial Truth is instituted.

0.050.M33: Finally, the God-Emperor had united the human race on Terra into a single nation as he always hoped for. With that, he begins the arduous process of restoring Humanity's power once again, determined to never let it fall again while he breaths.

0.050.M33-0.001.M34: The God-Emperor, along with his people, begins the process of repairing their nation and homeworld.

0.001-0.050.M34: The Imperium of Humanity is formed and begins recolonizing the Sol System and repair many of the ancient cities on Mars, Luna (the moon), Venus, and the Jovian moons (Jupiter's moons).

1.050.M34: The Sol System is soon returned to its pre-fall status. Human expansion temporarily stops for the moment (the warp storms still continued). The Emperor has scientists work on a new FTL-drive and other technologies to better face the dangers in the galaxy. He and many others were fully aware of just what was waiting for them on the other side of the warp storm surrounding their home system.

0.050-0.100.M34: After many years of research, scientists present to the Imperium their greatest discovery: a new FTL system called Slipspace that is separate to the warp. The technology is quickly mass-produced and implanted into any existing ships.

1.150.M34: After over 10,150 years trapped in their own star system, the warp storms finally begin to clear up and allow for clear traveling (it was unknown if slipspace could travel through a warp storm safely). It is soon discovered that particular human pyskers with special genes are able to perceive the warp and with slipspace in use (slipspace works on similar principles like the Immaterium, just far less chaotic and safer), it's an easy task for them to guide ships. These set of humans are referred as Navigators and they are soon given the position of guiding ships through slipspace.

3.150.M34-3.000.M35: The Imperium of Humanity begins to expand onto other star systems. The Imperial military, the Mechanicus, and other organizations are created along with the government. Most worlds the humans colonize contain ancient Human cities while some had alien structures that are added to the living layout. During the travels, certain pyskers tasked by the Emperor himself set up psionic shields throughout newly colonized space to ward off the influences of the warp, which proves successful. The Imperium begins to enjoy an age of discovery, exploring, and inventions. The Imperium size is roughly 4 Segmentums. However, in the two hundred and eighty-fifth century of the thirty-fourth millennia, the Imperium comes in contact with a race known as the Orks. Minor conflicts erupt against each other (the Imperium doesn't consider the orks a 'civilized race'). The conflicts, fortunately, don't threaten peace.

3.100.M35: The peace held in the Imperium starts to degrade over time by increasing ork WAAAAGGHHs and with groups/organizations of people demanding that the government either gives them full rights and self-governing like in the old-Earth nations; to keep Humanity "pure" by eliminating pyskers and outlawing augment implants; step down as they were corrupt; or other demands depending on the ideology of these people. These ideas were swiftly shot down by the Council of High Lords and the Emperor himself, as they are fully aware of how weak the Imperium of Humanity would become if such decisions or ideas were to be implemented in the Imperium.

4.200.M35: The protests from these group identified collectively as the Insurrectionists (even though many do not share the same goals but still work together) began with peaceful rallies but soon degraded to violence with most groups as they realized their original methods were not working. The breaking point came when rebels from the Vordian Oculus group made a daring attempted to overthrow the government on Hive world Krieg in a bloody revolution that resulted in parts of the planet reduced to radiation wastelands with billions of deaths and several hive cities destroyed. This action set off the spark for rebellions across Imperial space to break out. Martial law is declared in many worlds as the Imperium orders the arbiters and PDF forces to mobilize to restore order and put down the rebels.

2.322.M35: The situation with the Insurrectionists were looking grim for the government as reports piled in detailing small improvement with the rebels. For every cell they found and destroyed, another five would pop out of nowhere to continue the fight. It was at this moment, that a group of veteran Imperial Marines petitioned to High Command of the Imperial Military and the government of forming elite special forces of shock troopers trained for fast tactical attacks directly in enemy lines. Knowing that anything that could help destroy the rebels faster would be great, the idea was quickly approved and preparations were made.

2.397.M35: The newly created Special Forces branch of the Imperial Ground Forces is made with their main force: the Helldiver Shock Troopers. The new HDSTs are quickly deployed to the lines to combat against the rebels.

0.397.M35: With the introduction of the HDSTs, the destruction of the rebels steadily becomes a reality as entire groups are driven to extinction and others surrendering, but still many continue to fight. The Imperium becomes increasingly frustrated with putting down the rebels and began searching for new alternatives. The search continued until a brilliant scientist by the name of Dr. Catherine Halsey presents the idea of training super-soldiers with the best augments and armor the Imperium has to offer to better eliminate the rebels and at the same time guard against outside threats. In her report she explains that they could use the augments of the most advanced human genetics including those of the Emperor's own. Her project is given green light and work begins without pause.

0.411.M35: Deep within the keeps of the fabled Imperial Palace on the Himalayan Mountains, the Emperor, Dr. Halsey and other scientists succeed in birthing 21 young from natural fetuses donated from carefully selected women and biologically descended from the Emperor, the babies were classified as Project: Primarch, to become mankind's greatest people and the future of human evolution. Then came the question to the group on how to best raise them seeing as they were technically the Emperor's own sons (as the Emperor had admitted he feared he would be a terrible father and his responsibilities would greatly interfere). It is then decided to give them to the most prominent families in the Imperium to raise them with the heart of a human and with a diverse background.

2.412.M35: The young Primarchs are given to qualified families coming from different backgrounds that were selected for the environments they come from with each requested to raise them to the best of their ability of what it means to be truly human. During that time until they come to age, the Emperor spent his time when not handling his responsibilities to visit all of his children and have quality with them.

2.435.M35: After numerous years have passed by, the Emperor and his legendary Companion Guards, go forth around the Imperium of Humanity to reunite his children together after having all of them growing up and learning separately.

2.438.M35: After uniting all 21 of his children, he tells them of their origins, importance and how their genetics are crucial to the future of the Imperium and their people. He explains that they would each given a legion of super-soldiers to shape in their desire for the future of mankind and to serve as the Imperium's wrath and uphold peace and justice. They all agreed with pride and proudness of a son to his father.

2.452.M35: The first members of the 20 newly formed legions have already finished training and are assigned alongside their designated Primarchs.

2.488.M35: The first sanctioned Spartan Astartes along with their Primarchs are sent out to destroy the strongest rebel cells still remaining.

2.512.M35: The superior abilities of the Spartans have resulted in the near-eradication of most rebel groups with many of the survivors fleeing to frontier worlds to avoid death or going underground to avoid conflict. The program is considered a major success and plans to increase their numbers are approved.

2.512.M35-524.M35: The Imperium rebuilds the damages caused by the conflicts between the rebels and Imperial forces.

3.535.M35: With the backbone of the Insurrectionists crushed and the survivors scattered, the Imperium begins to focus on foreign problems (like the orks) and continues with the colonization/expansion. With the increasing number and strength of the military, the Imperium is soon able to repulse many ork WAAAAGGHHs before they can cause potential damage.

2.525.M35-524.M36: The Imperium of Man begins to slow down on expansion to avoid extending their borders to far and instead focus their attention on improving existing colonies.

6.524.M36: Agents of the Officio Agente, Sectium Xenos increasingly become worried about running into the borders of another alien empire and causing conflict that the Imperium may not need. Several members however carry suspicion of the existence of xeno empires due to their calculation regarding the large quantity of ruins found across Imperial space, many should have already been found by now. Especially concerning old pre-Imperial records detailing xeno species on worlds that would be found in their territory but seemingly no longer exist in all modern navigation records and "cannot be found" by Navigators. However, before they can write a report on it, Agri-world Harvest suddenly goes dark without warning.

6.525.M36: Contact with an alien empire called the Covenant of the Mantle occurs. They declare humanity 'unworthy' of the Precursor's gift (much to the confusion of the Imperium) and declare war for reasons unknown. The military and PDF forces are put on high alert and war preparations are set.

6.528.M36: After tensions were held, reports come in with news that Hive world Canis IV and Garden worlds Halima and Juldia are under attack by Covenant forces. After a quick meeting, the government unanimously declares a full war between the Imperium of Humanity and the Covenant of the Mantle.