The Precursors are the pre-eminent species in thegalaxy, moving beyond sentience into practical godhood. They can traverse galaxies in seconds, control evolution and create life.
The Precursors seed the Milky Way with life, looking toraise a species worthy of carrying on their stewardship ofthe galaxy.
The Precursors create the Forerunners and look to elevate them to rule the galaxy, but eventually deem them unworthy of the role. They also create humans.
The Forerunners go to war with the Precursors.
The Precursors create the Flood as a final test for both first generation humanity and Forerunners.
The Precursors are annihilated by the Forerunners. It isn't clear exactly how this happens.
150,000 BC: RISE OF THE FORERUNNERS
Forerunners have colonised much of the Milky Way thanks to Precursor technology. They are a now peaceful race and help elevate undeveloped races.
The first generation of humans begins colonising the galaxy using more technology left over from the Precursor era. Their civilisation grows to rival that ofthe Forerunners.
110,000 BC: THE FALL OF MAN
Humanity and the Prophets make first contact with the Flood and go to war.
Humanity retreats into Forerunner space and the Forerunners strike back.
Forerunner general The Didact leads his people to victory against humanity. Humanity is devolved into several different species and its colonies are destroyed.
Unbeknownst to the Forerunners, the human/Prophet alliance had successfully driven the few surviving Flood from the galaxy at the expense of victory against the Forerunners.
Who is... The Didact?
A Forerunner Promethean and the leader of the Forerunner military, the Didact lead his people to victory against humanity, but was imprisoned for his opposition of the Halo array. His original body was killed in 100,000 BC, and his consciousness found a new home in the body of Forerunner Manipular Bornstellar. The Didact once again took control of the military in the Flood/Forerunner war but his plans for fighting the Flood were rejected by the Forerunners' council, leaving only one option when Mendicant Bias broke their defensive line. His whereabouts after firing the array are unknown.
Certainly, the Didact survived the firing of the Halos. In his final transmission he tells the Librarian "I will begin our Great Journey without you,carrying this bitter record" - presumably, we suspect, joining the last of the Forerunners on their voyage out of the galaxy rather than taking the Covenant's version of the 'Great Journey' and dying with everyone else. The Didact and his armies will play a key role in Halo 4, but whether as friend or foeisn't clear.
Now residing in Bornstellar's Builder-class body, the Didact would lack the four metre-tall, 1,000 kilo body he had as a Promethean. In one of Halo Anniversary's Terminal videos, Guilty Spark remarks: "what I would not give to have a single company of Prometheans here. They would restore order with their trademark lethality, although... that would mean he would have to be here, too. And without the Librarian around to temper his rage, well... These Reclaimers might almost prefer the Flood."
BETWEEN 109,000 AND 101, 300 BC: THE PRELUDE TO WAR
The Forerunners learn of the Flood and begin planning construction of the Halo array as a 'Plan B' in case the Flood returns.
The Didact opposes construction of the Halo array and is sentenced to imprisonment on the newly-primitive Earth where his wife, the Librarian, makes her home.
Construction of twelve Halo rings begins, together with Shield Worlds intended to protect organic species from the Halos' devastating firing effect.
The Librarian begins archiving species from across the galaxy, placing samples of every species in sarcophagi on the Ark, far outside the Halos' effect.
100,300 BC: THE FLOOD/FORERUNNER WAR
Forerunners make first contact with the Flood on planet G617 g1. The investigating team are killed and the Flood escapes.
The Flood/Forerunner war begins. The Librarian hastens her work.
100,043 BC: MENDICANT BIAS
Forerunners create the Mendicant Bias AI to combat the Flood. It is placed in charge of Halo 07 and tasked with hunting the Flood Gravemind.
Halo 07 is test-fired, freeing the last surviving Precursor sealed away millennia earlier by Humanity. He is recaptured and imprisoned on Halo 07.
Mendicant Bias begins questioning the last Precursor on Halo 07. Their conversation lasts 43 years.
Since 343 took custody of the Haloverse they've published three novels tied directly to Halo 4. The first of the Forerunner Saga is Cryptum, telling the story of the Didact in 100,000 BC and establishing the complete history of the Forerunners and the original prehistoric human empire. It introduces the humans Chakas and Riser and sees the Forerunner Bornstellar become the new the Didact. The Didact eventually kills the man who imprisoned him, takes control of the Forerunner military, and heads off in search of his human friends Chakas and Riser, and the missing Halo 07.
100, 000 bc: THE BEGINNING OF THE END
The Didact is freed by the Forerunner Bornstellar after 1,000 years of imprisonment. They travel the galaxy together with the proto-humans Chakas and Riser. The Didact dies, but not before transferring his memories to Bornstellar who becomes the new the Didact. (Halo: Cryptum)
Manipulated by the last Precursor, Mendicant Bias returns on Halo 07 and turns on its creators, smashing the Forerunner capital. The new Didact takes control of the Forerunners' military.
Mendicant Bias seizes control of five of the twelve Halos. The Forerunners destroy them, leaving only seven.
Riser and Chakas journey to Halo 07 and help the Didact reclaimthe installation, restoring it to the Halo network. Chakas' mind is used as the template for 343 Guilty Spark. The last Precursor is revealed to be a Flood Gravemind and is killed by theDidact. (Halo:Primordium)
A Forerunner artefact bridging Earth and the Ark is buried in Africa by the Librarian.
Conversations between the Didact and the Librarian are recordedand stored on the Ark's Terminals (Halo 3).
Forerunners create the Offensive Bias AI to counter and fight Mendicant Bias.
Who is... The Librarian?
One of the Forerunner Lifeworkers, the Librarian relocated to Earth following the Human/Forerunner war and shepherded the devolved human species back towards civilisation. When her husband, the Didact, was imprisoned she placed a pre-programmed 'geas' in one group of humans, encouraging them over many generations to seek out the Didact's cryptum.
The two were briefly reunited on the Ark during the Flood/Forerunner war, but were separated when the Librarian continued her mission. In the final days of her life the Librarian constructed the artefact beyond Voi and forced Didact to activate the Halo array by preventing any possibility of her rescue. Somehow, she is still alive.
There is evidence in Halo Anniversary to suggest the entire Halo timeline is part of the Librarian's millennia-long plans. "Her strength was in planning and positioning the pieces, and then being bold enough to let it happen." says Guilty Spark in one of 343's Terminal videos. It took her 1,000 years to free the Didact and she did it without ever interfering directly. 100,000 years after her supposed death, other more secret plans are coming to fruition.
100, 000 B: THE END OF EVERYTHING
The following plays out in hours:
Mendicant Bias and the Flood fleet breach the Forerunners' defensive line and move onto the inner Forerunner colonies. Mendicant Bias commands a fleet of almost five million ships against Offensive Bias' tens of thousands.
The Didact fires the Halos, killing all sentient life within three radii of the Milky Way's centre.
Mendicant Bias' organic Flood ships are destroyed by the Halo array. Offensive Bias now outnumbers Mendicant Bias 6-1 and the battle swings Offensive Bias' way.
Four minutes later, the Flood/Forerunner war ends.
Mendicant Bias' AI is shattered by Offensive Bias. Parts end up on the Ark and on the Prophets' home-world.
SOME TIME SOON AFTER 100,000 BC: A FRESH START
Species archived by the Librarian on the Ark and various Shield Worlds are returned to their home planets by the surviving Forerunners.
The Forerunners exit the galaxy. Humanity is given the 'keys' to the Halo array in the Forerunners' absence.
The whereabouts of the Librarian and the Didact are unknown.
Primordium begins some time after 2556 with the Office of Naval Intelligence capturing a damaged Monitor identified as a duplicate of 343 Guilty Spark. This version of Spark goes on to recount how his personality is based on the ancient human Chakas and tells the story of how the Didact and a small group of humans recovered Mendicant Bias' hijacked Halo 100,000 years earlier. At the novel's climax, the Chakas/Spark Monitor seizes control of the ONI ship and sets a course for the Librarian's resting place, claiming she is still alive with the spirits of his old friends. The third book in the Forerunner trilogy has yet to be published, but will presumably cover the final months of the Flood/Forerunner war.
30,000 BC: HUMANITY RETURNS
Homo sapiens rise to become the dominant human species, eventually killing off the Forerunners' other human species on their journey out of Africa. The Neanderthals are among the last to die out.
The second generation of human civilisation emerges on Earth.
938 BC: THE PROPHET / ELITE WAR
Elsewhere in the galaxy, the Prophets and Elites already have vast interstellar empires thanks to knowledge inherited from the Precursors and Forerunners.
Humanity has developed numerous civilisations, but is thousands of years behind.
The Prophets and Elites go to war.
The Elites abandon their beliefs and begin studying Forerunner artefacts, accelerating their technological development.
852 BC: THE COVENANT
The Prophet/Elite War ends and the factions form a union named The Covenant. The Covenant adds further races over the next millennium as they colonise the galaxy.
Yuri Gagarin becomes the first human in space for 100,000 years.
Humanity's first off-world colony is settled on Mars.
Humanity forms the United Nations Space Command. The UNSC puts downrebels on Mars.
Humanity masters faster-than-light travel with the Shaw-Fujikawa Slipspace Drive.
Humanity has colonised over eight hundred worlds, including the planets of Reach and Harvest.
The UNSC abandons Project Orion - the first generation of Spartan super soldiers - because of expense and time.
Master Chief John 117 is born.
2517: THE SPARTAN II PROCESS
75 children are abducted and conscripted into the UNSC's Spartan II program. John is among them, and becomes squad leader shortly after training begins.
2525: THE HUMAN / COVENANT WAR BEGINS
The Human/Covenant War begins. Though it won't be revealed for many years, the Covenant attacked Humanity only after learning that Humans, not the Prophets were the Forerunners' favoured race.
The fourteen year-old Spartan IIs undergo extensive cybernetic and genetic modification. Thirty die, twelve are disabled.
The Spartans, equipped with Mjolnir Mk IV armour engage the Covenant above Chi Ceti IV, boarding and destroying a Covenant capital ship with the loss of only one man.
2531: HALO WARS
Troops from the UNSC Spirit of Fire engage Covenant troops of the partially-glassed planets Harvest and colony world Arcadia.
A gateway opened from Arcadia leads the Spirit of Fire to an isolated Forerunner Shield World where Humanity makes first contact with the Flood.
Sergeant John Forge detonates the Spirit of Fire's slipspace drive and destroys the planet. The Spirit of Fire's crew escapes and begins its long journey home in cryosleep. As of 2553, it has not made it back.
2532: SPARTAN III
The first 300 volunteer Spartan IIIs enter training. Cheaper and weaker than Spartan IIs, the IIIs are to be produced in much greater numbers with far fewer casualties.
Desperate for a propaganda victory, the UNSC makes the Spartan II program public. Spartan IIs become legendary. When killed, they are listed as Missing in Action to maintain the image of their invincibility.
2552: HALO REACH
While Earth still eludes them, The Covenant find Humanity's second home of Reach.
August 14 Noble Team takes down a Covenant Supercarrier. It is immediately replaced by hundreds more.
August 23 Noble Team helps evacuate city of New Alexandria. The city is glassed.
August 30 Noble 6, Emile-A239 and Carter-A259 die evacuating Cortana's AI core to the UNSC Pillar of Autumn. Then the Pillar of Autumn makes a slipspace jump using secret Forerunner data entrusted to Cortana.
September 19-22 The Forerunner data leads the Pillar of Autumn to Halo 04. John 117 is awoken from cryosleep and tasked with protecting Cortana and the location of Earth. The Pillar of Autumn crash lands.
John 117 makes contact with the Flood imprisoned in Halo 04's research centres. Halo's Monitor, 343 Guilty Spark, attempts to use John to activate the Halo array. Cortana prevents the activation and John detonates the crashed Pillar of Autumn's engines, destroying Installation 04.
In Halo: Anniversary, 343 Guilty Spark suggests the destruction of the Halo will awaken and anger the Didact.
2552: HALO 2 & HALO ODST
October 20 John 117 arrives on Cairo Station and is equipped with Mjolnir Mk VI armour.
Searching for the Ark, the Covenant accidentally discover the location of Earth. John returns home but quickly follows the Covenant's High Prophet of Regret's retreat back to Halo 05.
Earth is assaulted by Covenant forces searching for the Ark. An ODST squad in the city of New Mombasa engages in a series of skirmishes with Covenant ground forces.
November 2 John 117 arrives in Halo 05, assassinates the Prophet of Regret, and encounters the Flood Gravemind.
The revelation of the Halo array's true purpose creates a schism in the Covenant, turning the doubting Elites against the true believers from the Prophet-controlled races. The Gravemind uses it as an opportunity to seize the Covenant capital.
John 117 returns to Earth.
2552: HALO 3
November 17 John 117 ejects from the Covenant-controlled Forerunner Dreadnought and falls to Earth. The Forerunner artefact buried under the ocean near Voi is activated by the Covenant, opening a portal to the Ark.
December 11 Human and Elite ships arrive above the Ark and engage Covenant forces attempting to activate the Halo array.
John 117 and the Arbiter activate the replacement Halo 04 and escape through the Voi portal aboard the UNSC frigate Forward Unto Dawn. Halo 04's activation wipes out the Covenant forces, the Flood, and the Gravemind.
The activation closes the portal mid-transit. The Arbiter returns to Earth on December 23. John 117 is lost in space and enters cryosleep.
The Elites seize control of the Covenant. The Human/Covenant war ends.
A monument is erected in Kenya to mark the end of the war. Only five Spartan IIs remain alive, including the missing John 117.
The UNSC starship Infinity is completed, the first ship to use technology derived from Covenant and Forerunner sources.
The first Spartan IVs enter service aboard the UNSC Infinity. One Spartan II is equipped with Mjolnir Mk VII armour.
Humanity and the Covenant begin a long period of post-war recovery (Halo: Glasslands).
2556: LOST IN SPACE
Cortana files a report aboard the adrift Forward Unto Dawn concerning the shared history of the Forerunners and Humanity. She is showing signs of madness. (Halo Legends: Origins)
A duplicate of 343 Guilty Spark recounts Chakas' story from the Forerunner/Flood war. He later seizes control of an Office of Naval Intelligence ship, puts the crew to sleep, and sets course for the Librarian's last known location, claiming she is still alive (Halo: Primordium).
The first of 343's post-war novels follows Spartan creator Dr Catherine Halsey inside the Forerunner planet of Onyx, and the team tasked with bringing her to trial for the crimes committed in pursuit of the Spartan II program. 343 have confirmed events in Glasslands will lead into Halo 4, and it's likely the casual references to the hyper-advanced UNSC Infinity and Spartan IV program are very deliberate seeds planted for the Reclaimer trilogybeginning in Halo 4. Glasslands ends with Halsey inONI custody, the galaxy at peace, and with humanity adopting Covenant and Forerunner technology into their existing tech.
BEYOND 2556: HALO 4
Master Chief John 117's Mjolnir VI armour is upgraded with a jet pack and other modifications, as seen in the 2011 Rebirth trailer.
The Forward Unto Dawn drifts into orbit with a Forerunner Shield World and is consumed by the planet's outer sphere.
An ancient threat rises.
WHAT DOES THIS MEAN FOR HALO 4?
Halo 4 is a different way to make a Halo game. Over five games Bungie wrote the Halo timeline and edited it whenever it was convenient - ignoring Eric Nylund's Fall of Reach novel to make Halo: Reach and squeezing the Microsoft-mandated ODST expansion into the series. Halo's new team at 343 Industries didn't write the timeline, but their fresh start and the studio's total ownership of the games and extended universe means they're respecting the timeline more than Bungie ever could.
The maps, characters, and technology in Halo 4 all have roots in Halo's games, novels, comics and animated movies. For the first time, the multiplayer mode ties to the campaign and offers up a good reason for red Spartans to fight blue Spartans, on maps ripped straight from Halo's extended fiction. Wraparound is a classic circular Halo deathmatch map - allelevation changes and steely surroundings on a Forerunner shield world. Warhouse is a civilian construction facility orbiting a gas giant where automated machines build a towering UNSC Cyclops Mk II mech - an evolution of Halo Wars' Mk I - as a war plays out at the giant's feet. Nope, you won't be able to pilot the mech, but that's okay; 343 say there'll be even bigger vehicles in the campaign.
Karen Traviss' post-Halo 3 novel Glasslands introduced the fourth generation of Spartans to the Halo universe and sent a Spartan II into battle with the UNSC's first suit of Mjolnir Mk VII armour. It's those Spartan IVs who'll star in the multiplayer mode, and every Spartan IV is equipped with the slimline new armour. Multiplayer perks are tied to components that let you create custom classes and looks on the fly, equipping extra armour, stronger shields, or more exotic armour abilities.
It's not a great stretch to expect the Master Chief's own jet pack to be among the custom parts. The Chief leaves the Ark at the end of Halo 3 wearing Mjolnir Mk VI Powered Assault Armour, but he emerged from his cryotube in last year's Rebirth trailer wearing a new Mjolnir variant.
Return of the Chief
It's possible the Chief emerged from the tube for some upgrades between Halo 3 and 4, or - more likely - 343 will bodge it and say there was a prototype Mk VII suit knocking about on the Forward Unto Dawn all along. The first suit of Mjolnir VII armour was tested by a Spartan II in the post-war novel Glasslands, so an early prototype on the Forward Unto Dawn suit is almost credible, but let's hope 343 have a cleverer explanation that that, eh?
In any case, 343 are respecting the timeline when they gave the Chief's new armour a jet pack module - the Mjolnir armour abilities were first introduced on Reach's battlefield as a new innovation in 2552, but the early prototypes never made it off Reach so they skipped Bungie's Halo trilogy. Armour abilities should be standard issue after Chief's three-year kip.
Every Spartan in Halo 4's multiplayer can sprint as standard, meaning Chief is equipped with at least two of Reach's armour abilities - the Jet Pack and Sprint modules. We're speculating here, but it's possible the Chief's new gear could include the Active Camo, Decoy and Dropshield systems, too, while multiplayer would use them as expensive custom components on your upgraded armour. "We want to give players a greater sense of empowerment through choice," says creative director Josh Holmes; built-in armour abilities would let 343 improve on some of Reach's features while giving Chief more options. It would be a crucial step in modernising Halo and giving you more choices on the battlefield.
Countdown to E3
"One of our goals was very gameplay focused" says executive producer, Kiki Wolfkill. "It's about providing a really visceral first-person experience and what it feels like as a player to embody Chief, really delivering on that fantasy of being a 900 pound Spartan." There are more CoD-style moments where you'll see life in the suit, tearing open doors and hanging from precipices in first person.
"Our other goal revolves around storytelling and character development," she adds. "There's such a rich fiction around Master Chief that exists in other mediums which haven't traditionally been experienced through the games. There's going to be a very ancient, very dark threat, and the decisions he's going to need to make and the things he'll need to overcome will really start to define him a little differently as a character."
The game-changing secrets will have to wait until June's E3 showcase. Expect the first campaign reveal live on Microsoft's stage, and expect the best from Microsoft's dream team; they've had a billion years to work on it, after all.