Highlights

  • The Halo timeline is comprised of seven major eras, each filled with significant events and conflicts, some of which have never been depicted in the games.
  • The Forerunner era showcases the rise and fall of the technologically advanced Forerunner species, who ultimately create the Halo Array as a last resort to combat the Flood.
  • The Great Human-Covenant War is a pivotal period in the Halo franchise, with humanity battling against the Covenant and the introduction of iconic characters like Master Chief and Cortana.

All the way back in 2001, the first Halo hit store shelves, and became an overnight sensation. A Sci-Fi first-person shooter like nothing gamers had seen on consoles before, Halo garnered an immediate fan-base thanks to its smooth controls, open-ended gameplay, and its surprisingly deep cinematic narrative. While it was clear Bungie had a good idea of Halo's universe going into that first game, there's no way the developer could have known where the series would end up two decades later.

The current Halo timeline consists of seven major eras, and even that excludes some of the smaller events in the timeline. From the monumental Forerunner-Flood galactic war that essentially acts as the catalyst for the entire Halo franchise, to much smaller-scale conflicts like the insurrection against the UNSC, the Halo timeline has no shortage of big events, many of which have never actually appeared on-screen in a Halo video game.

Halo 's timeline uses the phrases "BCE" and "CE" to refer to its eras, meaning "Before Common Era" and "Common Era" respectively. Essentially, CE refers to the period of humanity that Halo mostly revolves around.

Halo Wars 3
Related
One 2024 Halo Project Proves It's Time for Halo Wars 3

The Halo franchise is trying its best to pull things back on course and there's one 2024 Halo project that proves it's the right time for Halo Wars 3.

The Major Early Eras of The Halo Timeline Explained

The Precursor Era - Unknown to 200,000 BCE

The first major era on the Halo timeline, and one that's essentially missing from the vast majority of Halo video games is the Precursor era. Taking place roughly 200,000 years before the first Halo game, the Precursor era focuses on the titular ancient alien species as they spread their extremely advanced technology and military might across the galaxy. Viewed as gods by most of the galaxy, the Precursors use their absurdly powerful armies to defeat The Flood when it first appears, but during this war, The Forerunners gradually build their own advanced empire, and with the Precursors' forces weakened, the Forerunners manage to wipe the Precursors from existence within 200 years.

The Precursors technically come from a whole other universe and may have created every important species in the Halo franchise, but this backstory could be rewritten at any time due to its far-fetched nature.

The Forerunner Era - 200,000 BCE to 50,000 BCE

With the whole galaxy at its feet, the Forerunners become the reigning species, with its empire stretching across the entire Milky Way. A proud yet self-reflective species, the Forerunners believed that they were caretakers of the galaxy, though one day this "Mantle of Responsibility" would be handed down to another species, just as they believed the Precursors handed it down to them.

Around 100,000 years into its reign, the Forerunners were forced into a war with humanity, which had been slowly expanding across the galaxy since the Precursor era. Believing them to be expanding just for the sake of it, the Forerunners decided to take swift action against humanity, essentially wiping them out and punishing them by exiling them to their home planet, and stripping them of all technology. However, humanity only started expanding across the galaxy in an attempt to escape The Flood, which had somehow returned and now threatened the entire galaxy.

What followed was a 300-year war between the Forerunners and Flood, with the former using all of its advanced weaponry to attempt to exterminate the parasitical species. With nothing being able to stop The Flood, The Forerunners decide to take drastic measures. The Forerunners create the Halo Array, a series of ring-worlds designed to cleanse the entire galaxy of life, and thus kill The Flood by eliminating its food source. The Forerunners fire the Halo Array, but not before saving and preserving many of the galaxy's species on the Ark.

The Rise of the Covenant - 50,000 BCE to 1500 CE

Many years after the firing of the Halo Array, the galaxy's saved species were freed from preservation and sent back out into the galaxy, essentially restarting every species' timeline from scratch. Eventually, an alien species known as the San'Shyuum discovered ancient Forerunner technology and formed a religion based around it, which began to dominate the species' entire way of life.

During the species' quest to seek out all Forerunner artifacts in the galaxy, the San'Shyuum stumble upon the Sangheili species, who themselves had formed a religion around these artifacts. However, while the San'Shyuum believed in using these artifacts to advance their technology, the Sangheili strongly believed that they should not be disturbed, which resulted in a near-century-long war. Both on the brink of extinction, the Sangheili and San'Shyuum decided to stop fighting, and instead join forces, marking the start of The Covenant. Over thousands of years, The Covenant continued to add more species to its alliance, all the while humanity was undergoing its own changes.

Master Chief over Mass Effect 3 screenshot-1
Related
After The Master Chief Collection, Halo Should Follow in Mass Effect's Footsteps

When it comes to Halo's future, Microsoft should follow BioWare’s lead and try something new with the next entry in its most famous franchise.

Humanity and the Halo Games on the Franchise Timeline

The Colonial Era - 2362 CE to 2494 CE

After following a history nearly identical the real world, Halo's humanity begins to colonize the planets surrounding Earth. After a brief Interplanetary War between the systems, humanity established the United Nations Space Command, and the discovery of the Shaw-Fujikawa Translight Engine allowed humanity to spread itself across more of the galaxy, including on planets such as Harvest and Reach.

The Insurrection - 2494 CE to 2525 CE

Now established throughout the Milky Way, humanity started to experience a bit of a political schism. Many of the outer colonies believed that the UNSC is controlling them, and began an insurrection in order to gain their freedom from the government. In an attempt to stop this building conflict, the UNSC approved Dr. Halsey's controversial Spartan program, which saw the kidnapping of thousands of children across the galaxy in an attempt to make an army of genetically modified super soldiers.

The Great Human-Covenant War - 2525 CE - 2553 CE

Above the planet of Harvest, a small Covenant ship came into orbit. Believing the planet to be home to thousands of Forerunner artifacts, the Covenant landed, only to realize that the planet was already occupied by humanity. After an Unggoy accidentally fires on a UNSC marine, the Covenant begins a skirmish on the planet, eventually destroying it via an orbital plasma bombardment known as Glassing. The San'Shyuum soon discovered that humanity had been chosen by the Forerunners to be its successor, and in an attempt to stop that from happening, they declare war on humanity.

After about 30 years of non-stop conflict, the Covenant stumbled upon humanity's central planet of operations, Reach, and began an immediate full-scale invasion. This battle saw the vast majority of humanity's forces get completely wiped from existence, including most of the UNSC's Spartans, and Reach is left utterly destroyed. The Pillar of Autumn, one of the UNSC's light frigates, managed to escape Reach right at the last second, and after making an uncalculated Slipspace jump, it appeared right in front of a Halo ring-world.

Thus begins the events of the original Halo trilogy. After destroying this Halo ring, the Master Chief and his AI companion Cortana headed back to Earth, only for it to be attacked by Covenant forces. The San'Shyuum betrayed their Sangheili allies soon after, a move that eventually causes the Sangheili to side with humanity. With the Sangheili on its side, and The Flood wreaking havoc on The Covenant's forces, humanity manages to win the war.

The Reclaimer Era - 2557 CE to 2560 CE

After a brief hiatus in cryosleep, the Master Chief awakened in the year 2557 CE, and stumbled upon a Forerunner Shield World known as Requiem. Here, the Master Chief encountered and killed the ancient Forerunner Promethean named the Ur-Didact. Around the same time, a Sangheili named Jul 'Mdama attempted to resurrect The Covenant, but his plans were foiled. This current era of Halo goes all the way up to Halo Infinite, which sees the Master Chief land on Zeta Halo and attempt to fend off The Banished, a collection of species that rebelled against The Covenant, but who are now searching the Halo ring-worlds for artifacts of power.