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Halo timeline: Precursors, Forerunner betrayal, and the era that followed

Complete Halo timeline series

With a universe as jam-packed full of complex lore as Halo's, it's hard to believe that there was a time when the Milky Way galaxy was barren. However, that is exactly the case. There was a period in which nothing lived; the entirety of the galaxy was devoid of life. It was not until the arrival of the Precursors that the Milky Way became a home for biological life forms.

The Precursors: A species unlike any other

The Precursors were not limited to any one physical shape, and they possessed the ability to shape-shift into any desired physical form.

The Precursors were not limited to any one physical shape, and they possessed the ability to shape-shift into any desired physical form.

The Precursors were the closest thing to divine beings in the Halo canon.

The Precursors were described as being "trans-sentient", or beings that were able to connect with the very fabric of the universe. Possessing the ability to travel seamlessly through the universe, they arrived at the Milky Way, only to find it completely empty. Using their advanced powers, they seeded the galaxy with life.

As time went on, the Precursors decided to give the most technologically advanced species they created something called the "Mantle of Responsibility," an honorable and noble position, in which the species would act as the protectors and guides for the lesser races in the galaxy. Their first species chosen for this role was the Forerunners.

This concept art of a Forerunner city was done for a (canceled) Halo project that was originally going to be developed by Ensemble Studios.

This concept art of a Forerunner city was done for a (canceled) Halo project that was originally going to be developed by Ensemble Studios.

The Forerunners were considered to be the most advanced race in existence, after the Precursors.

The Forerunners were determined to be nearly as intelligent and advanced as the Precursors themselves. Because of this, they were the race chosen to hold the Mantle. Initially, the Precursors saw the Forerunners as the pinnacle of galactic society, and for a time the Forerunners held the Mantle and maintained order throughout the galaxy, watching over all sentient species. However, over time, the Forerunners became arrogant and corrupted, believing themselves to be superior to every other species. While this may have been true from a factual standpoint, an egotistical and selfish rule was not what the Precursors had intended the Mantle's holders to create and enforce. Therefore, the Precursors stripped the Forerunners of their possession of the Mantle, and instead looked towards ancient humanity to see if they were worthy to hold the Mantle. While less advanced than the Forerunners, ancient humanity was considered humble and responsible enough to possess the Mantle.

Forerunner betrayal: A savage and selfish act

In response to the change of power, the Forerunners launched a brutal revenge strike against the Precursors for stripping them of the Mantle. Despite the Precursors' superiority in almost every way, the Forerunner betrayal took them completely by surprise. Before the Precursors could make a defensive stand, the Forerunners slaughtered almost every single one of their creators. The Precursors had gone from being the ultimate power in the galaxy to a shell of their former selves in what seemed like the blink of an eye.

The aftermath

Upon the conclusion of the Forerunners' rebellion against the Precursors, the galaxy entered an era of relative peace. Aside from occasional civil wars that occurred in sections of the Forerunner empire, the Forerunners continued their role as the Mantle's holders.

At the same time, the last few remaining Precursors used their abilities to transform themselves into a kind of molecular dust. In this form, the Precursors intended to wait millions of years, hiding from their killers and waiting for the perfect opportunity to return to their past forms and exact revenge on the Forerunners. However, the DNA compositions of the powder became corrupted over time, and as a result, life forms that came into contact with it would experience insanity and even physical mutations. This was the very first form of the Flood, a parasitic life form that the Precursor dust would eventually mutate into upon coming into contact with humanity.

Humanity comes into contact with the Flood — and the Primordial

The Flood mutated into their current state by infecting domesticated human animals.

Ten million years after the conflict between the Forerunners and the Precursors, ancient humanity came into contact with the Precursor dust. When given to domesticated animals, the powder appeared to improve the behavior of the pets, making them more docile. However, humanity was unaware that the dust retained the sentience and intelligence of the Precursors and was only improving the behavior of the animals to mask their true actions: altering and mutating the genetic code of the pets.

Ancient humanity was taken completely by surprise by the rise of the Flood parasite.

Ancient humanity was taken completely by surprise by the rise of the Flood parasite.

Once the dust fully took control of the animals, the now Flood-controlled pets began to kill and infect their human masters. This was the beginning of the first Flood outbreak. Attacking with unexpected and sudden ferocity, humanity's empire quickly began to fall to the parasite.

Due to its mutations over time, the Primordial looked nothing like other Precursors.

Due to its mutations over time, the Primordial looked nothing like other Precursors.

The Primordial was the last surviving Precursor, an ancient being from an ancient time that humanity hoped would provide answers and solutions.

At the same time, the humans discovered a being known as the Primordial, the last surviving Precursor, in a capsule located within the center of a planet. Unlike the rest of the Precursors who had become molecular dust, the Primordial chose to seal itself away, mutating its form over time to survive for eons. Human scientists brought it to the human capital world of Charum Hakkor to study it. When asked about the Flood, however, the answer was apparently so horrifying to the humans that they committed suicide.

With the Primordial not offering anything that could help them against the Flood (likely because the Flood were previously Precursors and thus would be on the same side as the Primordial) and knowing conventionally that they couldn't defeat the Flood, the humans chose instead to flee — directly into Forerunner-controlled space.

Human-Forerunner war: A desperate, bloody conflict

The Human-Forerunner War was a conflict of misunderstanding, caused by Flood manipulation.

When the Forerunners saw humanity entering their territory with a massive fleet, they assumed it to be an act of war. Mobilizing its army of warriors, the Forerunners assaulted the incoming forces.

Humanity, in a desperate struggle, fought the Forerunners with an unparalleled fierceness, leading to heavy Forerunner casualties. Meanwhile, the Flood chose to withdraw from their conflict with humanity, tricking the Forerunners into believing that humanity had driven them off. In fact, due to their sudden withdrawal at the start of the Human-Forerunner War, many Forerunners found the Flood as nothing more than an excuse for humanity's expansion into their territory.

The Flood did this for two reasons. One reason was that the Flood (with Precursor motives) felt that the time to test humanity for the position of Mantle holder was not right. Another was that they wanted to disappear, throwing off Forerunner investigation into the Flood and making them believe the threat was not nearly as dangerous as it was. The Flood's hope was that through this sudden retreat, the Forerunners would be ignorant of the Flood's power and thus be ill-prepared when the Flood exacted revenge on them for the Precursor genocide millions of years prior.

Downfall of ancient humanity

The Forerunners assaulted and subsequently conquered every human world, leaving no survivors in their wake.

Following the Flood retreat, humanity was left to face a race that was superior to them in every way. Despite fighting them ruthlessly, the Forerunners hunted humanity to extinction for its assumed invasion of Forerunner space. One by one, human strongholds fell, until finally, humanity was ultimately defeated on its homeworld Charum Hakkor. While there, the Didact (the leader of the Forerunner military) discovered the Primordial that humanity had captured. The Didact proceeded to interrogate it, and he chose to keep the dialogue between them secret from everyone. After this, the Forerunners decided to keep the Primordial trapped in the stasis capsule it was found in.

As punishment for what the Forerunners saw as an act of aggression on their homes, humanity was stripped of their advancements and regressed back to their origins of hunter-gathering and cave-dwelling. The Forerunners seeded humanity on their homeworld of Earth, where they would be forced to evolve again. This effectively marked the end of the ancient human empire.

A peaceful era

After the defeat of the humans, the galaxy entered another age of relative peace. While arrogant and self-centered, the Forerunners nonetheless served their duties as holders of the Mantle by watching over the rest of the galaxy. For most Forerunners, the Flood were nothing but a hoax, a misleading lie that was meant to distract them from seeing humanity as the real threat. However, some Forerunner leaders secretly knew that the Flood were very real, and as such, remained watchful for the return of the parasite.

The Flood themselves would remain poised at the edge of the Milky Way galaxy, biding their time and waiting for the perfect opportunity to strike down the Forerunners and exact revenge on them for their genocidal actions.

Your thoughts

What's your opinion on the origins of the Halo universe? Let us know in the comments.

Brendan Lowry is a Windows Central writer and Oakland University graduate with a burning passion for video games, of which he's been an avid fan since childhood. You'll find him doing reviews, editorials, and general coverage on everything Xbox and PC. Follow him on Twitter.

20 Comments
  • Thanks, this helps a lot!
  • That's a whole lot of Halo novels that I do not have to read now.  Thanks!!!! Don't get me wrong, I love reading - spent the bulk of my youth reading hundreds, potentially thousands of books, etc. Just that age brings responsibilities, and less down time. And with very few down time hours, one has to choose very selectively what to expend it on.  Sleep gets the bulk of that.  Time with family, and things you can do with family (TV, movies, games, etc.) comes in second. Books are a solitary endeavor, so you can imagine where they come in on the hierarchy of options for down time activities.  In the case of Halo, I got as far as Contact Harvest . . . and haven't [been able to] touched a single book in the series since.  And truth be told, single-player campaigns in games have become nearly as hard to invest free time into as books have become. 
  • Great article! I loved the Forerunner saga books. I hope the return on the Flood in Halo Wars 2 will show us some answers about the Precursors or Mendicant Bias
  • Wow. The whole "Pre-Cursors", "Forerunners" bit sounds like it was directly ripped off from Babylon 5 and it's "First Ones" and "Shadows/Vorlons".
    Excellent show Babylon 5. Pity that Warner Bros. screwed up the transfers so badly on the DVD/Blu-Rays all because they are cheap.
    Just think what someone like HBO could have done with a show with the breadth and scope of Babylon 5.
  • Reminds me a bit of the Ancients and Ori from Stargate SG-1
  • I really like the Halo games (including Halo 5's campaign) but the concept of an ancient human civilization that was defeated and then erased to the point there is no arqueological evidence to be found, is too much bs to my taste.
  • Well the forerunners were very powerful. And I'm pretty sure there is archeological evidence of ancient humans.
  • If people are just now (the MC era) discovering Forerunner artifacts, and that only due to the Covenant, this doesn't seem too odd. Give some more time and things may surface.
  • There is virtually no way we wouldn't discovery a technological civilization from the past since the half of the mid-XX century. There would be a layer of weird minerals that couldn't be explained by any other mean than a technological advanced civilization. A much better explanation was to say the Forerunners took some humans to another planet and they developed an advanced civilization there.
  • They changed our homeworld. We were re-seeded onto a planet that did not have our archeology. More to the point, the Forerunners did leave a portal on Earth (seen in Halo when the Convenant invade), which was burried in a singular location in Africa. I do think that, if buried deep enough, an alien race could hide something on Earth without us knowing as long as they didn't bury all sorts of their stuff across the globe. Given enough of a technological advantage, you could probably even make the burried object look like a crappy rock that is not worth digging into.
  • Just echoing what pickypg said, but per the Halo universe, humanity was not originally from Earth if my understanding is correct. That would mean that there is still lots of universe to explore, and ancient advanced human technology may still be discovered. Remember, human archeologists have just recently been clued in that there are alien lifeforms of any kind fairly recently, and advanced early civilisations more recently yet. The librarian did tell MC in Halo 4 that humans had traveled the stars before, and even gave the Forerunners a run for their money for a while. People would have just really started surveying and searching recently, and it is a big universe after all. Who knows what the writers will dream up. Halo has some of the best story potential of any franchise out there in my opinion, even on par with heavy hitters such as Star Wars.
  • The problem is that there is no possible way humanity is not from Earth. Pretty much everything in biology indicates humans share evolutionary history with all other life in this planet. I am a biologist and perhaps this bothers me more than most people but it really breaks the setting's believability. Anyway, despite that, I really enjoy the Halo saga and I look forward to the next installments.
  • Well, I completely discount the possibility of there being aliens, so I guess we're even. It is science FICTION after all right? Some suspension of belief is unavoidable I suppose. Either way I also am excited to see what comes next.
  • I like Halo multiplayer.
  • Good write up. I had read the Forerunner trilogy so I knew that section, but I knew nothing of the Precursors. Other than maybe they existed. Now I'll have to see if I can scrape together the time to do some reading. The Halo universe is definitely an interesting one with lots of room for good story telling. They just have to leverage it all.
  • Thanks for this. Really cleared up some of this lore from the newest games.
  • Just a reminder that 343 is a bunch of morons for how they threw the Didact away in a comic between the last 2 main games. He was a decently interesting character, then we get left with useless drones like Locke and Warden...
  • man this is garbage...
  • Then do it better and we will judge your artistic skills of story telling and see who wins.
  • Here in 2021, I finally found the time to start on this timeline. Thank you writing it many years ago, Brendan. It cleared many confusing aspects of Halo 1 (I am only just now playing the series through)