A timeline of all major events in the Halo universe from the time of the Forerunners through the rule of the Created.
2142 CE
In 2142 CE, the Unggoy were discovered on their homeworld of Balaho by the Covenant and forcibly added to their list of member species.
The Jovian Moons Campaign was a brief conflict in 2160 between the corporate-backed Friedens and the neo-communist Koslovics on several of the Jovian moons, spurred by a Frieden attack on a team of colonial advisers sent by the United Nations to help police the often violent region.
The Rainforest Wars was a large-scale conflict from 2162 to 2163 between the fascist Friedens, the neo-communist Koslovics, and the forces of the United Nations on the continent of South America.
The Mars Campaign was a retaliatory strike in December 2163 by the United Nations to eliminate the Koslovics, a rebel organizations labeled as terrorists by the UN.
The Interplanetary War was a six-year conflict between the United Nations, neo-communists known as the Koslovics, and the corporate-backed Friedens, an movement with strong fascist roots.
The Shaw-Fujikawa Translight Engine, informally known as an FTL drive or slipspace drive, was invented by a team of scientists led by Tobias Fleming Shaw and Wallace Fujikawa and unveiled to humanity in April 2291.
The first permutation of the Orion Project, the predecessor to the future Spartan programs in the 26th century, was initiated on April 13th, 2321, consisting of five test candidates.
The Domus Diaspora was a time period during humanity’s expansion into the galaxy that saw massive colonization efforts of hundreds of colony worlds in the span of around thirty years, starting in 2362.
The colony world of Reach, the first ever extrasolar colony established by humanity, was colonized sometime in 2362 by the colony ship Odyssey.
The colony world of Arcadia, one of the many outer worlds to be colonized in the 25th century, was settled sometime in 2429.
The colony world of Meridian, a moon orbiting Hestia V in the Hestia system, was an outer colony world colonized sometime in 2431.
2462 CE
Following years of abuse of Unggoy at the hands of the Kig-Yar culminating in the sterilization of thousands via poisoning, the Unggoy Rebellion began in 2462 to protest their treatment by the Kig-Yar and the Covenant as a whole.
The outer colony world of Harvest, one of the youngest human colonies, was settled sometime in 2468.
~2470 - 2480 CE
Sometime prior to the Jiralhanae’s inclusion into the Covenant in 2492, a decade-long civil war known as the First Immolation devastated the Brute homeworld of Doisac and reduced the Jiralhanae society to pre-industrial technologies.
In 2491, the Office of Naval Intelligence re-instituted the Orion Project, an attempt to create engineered super-soldiers to boost combat effectiveness.
The Far Isle Rebellion was a major uprising on the outer colony world of Far Isle in 2492 that is largely cited in spurring the Insurrection.
2492 CE
In 2492, soon after the end of a devastating civil war between Jiralhanae that caused a total collapse in Jiralhanae society, the Covenant visited the Brute homeworld of Doisac and invited them to join.
The Callisto Incident was a series of events involving the UNSC Callisto that is considered the first true insurrectionist attack from January to March 2494.
Operation: TREBUCHET was a twelve-year UNSC operation to quell growing unrest and insurrectionist activities in the outer colonies from 2513 until the start of the Human-Covenant War in 2525.
The Spartan II program, led by Dr. Catherine Halsey, was a plan by the Office of Naval Intelligence to use children with superior genetic traits to create a group of super-soldiers in order to put an end to the ongoing Insurrection in the outer colonies.
The First Battle of Harvest was humanity's first contact with the Covenant on the planet Harvest in the Epsilon Indi system and the subsequent destruction of the entire colony.
On their first mission as fully augmented Spartan-IIs, Blue Team, consisting of John-117, Samuel-034, Linda-058, Kelly-087, and Fred-104, infiltrate Eridanus Secundus, a hidden United Rebel Front base located in an asteroid field, and capture Colonel Watts.
The Battle of Chi Ceti was a battle between the UNSC Commonwealth and the Covenant vessel Unrelenting in the Chi Ceti system on November 27th, 2525.
The Second Battle of Harvest, also known as just simply the Battle of Harvest, was humanities first attempt to recover the planet Harvest from the Covenant, who wiped out the existing colony and killed tens of thousands of civilians a year earlier.
The Harvest Campaign was a five-year campaign to retake the planet Harvest after the Covenant took over the planet and wiped out the colony on Harvest.
Operation: SILENT STORM was a UNSC operation to use EVA tactics to infiltrate Covenant vessels and either capture or destroy them from within early in the Human-Covenant War in March and April 2526.
The Battle of Mesra was a Covenant attack on the human outer colony world of Mesra in late May to early June 2526.
The Battle of Netherop was a conflict between UNSC forces led by Spartan-II Blue Team and Covenant forces on the uninhabited hothouse world in June 2526.
The Battle of Alpha Aurigae was a large naval battle between UNSC and Covenant forces in the Origami Asteroid Field of the Alpha Aurigae system, culminating in a UNSC victory.
The Fall of Madrigal was an early battle in the Human-Covenant War, occurring on and around the planet Madrigal in the 23 Librae system.
The Battle of Hat Yai was a battle early in the Human-Covenant War that took place between late 2528 and early 2529.
Sometime in 2530 the colony world of Eridanus II, home world of John-117, was glassed by an unknown Covenant force.
The Battle of the Great Bear was a naval battle between a UNSC fleet of seventeen warships and three Covenant warships in the Groombridge-1830 system.
Operation: SMOKING ACES was a raid by Spartan-II Blue Team on an Insurrection stronghold in the 111 Tauri system.
Spartan-III Alpha company was the first of three Spartan-III companies to be recruited, trained, and put into service.
In an effort to limit the ability for the Covenant to discover human colonies, including the inner colonies and Earth, the Cole Protocol was established to wipe all ship navigation data when the UNSC came into contact with any Covenant forces.
The Battle of Jericho VII was a three-day naval and ground battle pitting the UNSC versus the Covenant forces in the Lambda Serpentis system.
The Battle of Charybdis IX was a Covenant assault on the planet Charybdis IX in the Charybdis system sometime in 2535, prior to the Battle of the Rubble.
The Battle of the Rubble was a battle that took place in the 23 Librae system on a grouping of Lagrangian asteroids trailing Hesiod, a gas giant in the system, some time around 2535.
The Battle of Metisette occurred in the immediate aftermath of the Battle of the Rubble in 2535, taking place on Metisette, the nearby moon of the gas giant Hesiod.
The Battle of Leonis Minoris was a battle between Covenant and UNSC forces in the Leonis Minoris system sometime in 2537.
The Battle of New Harmony was an assault on the colony New Harmony by Covenant forces in early 2537.
The Battle of New Constantinople was a large conflict between UNSC and Covenant forces that took place some time in early 2537 on the colony of New Constantinople.
Operation: PROMETHEUS was an assault on a Covenant shipyard located on and around asteroid K7-49 by Spartan-III Alpha Company.
The Battle of Kholo was a Covenant assault on the human colony world of Kholo sometime in 2539.
Spartan-III Beta company was the second of three Spartan-III companies to be recruited, trained, and put into service.
The Battle of Psi Serpentis was a major conflict between a UNSC fleet of 162 warships led by the UNSC Everest and Admiral Preston Cole and two fleets of Covenant warships totaling over 300 ships in the Psi Serpentis system in April 2543.
The Battle of Miridem was an engagement between human and Covenant forces on and around the colony of Miridem.
The flagship of the UNSC Navy and the first Infinity-class supercarrier ever constructed, the UNSC Infinity is the largest single human warship ever constructed, with a crew of over 17,000.
Spartan-III Gamma Company was the last of three Spartan-III companies to be recruited, trained, and put into service.
Operation: TORPEDO was a mission by Spartan-III Beta Company to infiltrate and destroy a Covenant refinery on Pegasi Delta, the moon of 51 Pegasi B in the 51 Pegasi system.
The Battle of Skopje was a conflict between the Covenant and UNSC forces on the colony world of Skopje, sometime in 2547.
In an effort to boost morale, the Office of Naval Intelligence made public the existence of the Spartan-II program and the accomplishments of the Spartan-IIs in May, 2547.
The Algolis Invasion was a Covenant attack on the human colony world of Algolis in the Algol system sometime between 2548 and 2552.
The Battle of Ballast was a conflict between Covenant and UNSC forces on and around the colony of Ballast in 2551 or 2552.
The Battle of New Jerusalem was a Covenant attack on the colony of New Jerusalem in the Cygnus system sometime in July or August 2552.
Operation: RED FLAG was a planned operation by both the Office of Naval Intelligence and the UNSC to use Spartans to capture a Covenant ship, use it to penetrate into Covenant space, and capture a Hierarch, with the intent of using the Prophet to broker a cease-fire.
The Fall of Reach was possibly the largest battle during the Human-Covenant War, taking place in the Epsilon Eridani system, in orbit and on the ground of Reach, humanity's largest military stronghold.
The Battle of Tribute was a large-scale invasion of the colony world Tribute in the Epsilon Eridani system by Covenant forces during and after the Fall of Reach in 2552.
The Massacre at Eridanus Secundus was a Covenant attack on a rebel facility within a series of asteroids in the Eridanus system in late 2552.
Operation: FIRST STRIKE was a mission undertaken by John-117 and several other Spartan-IIs to infiltrate and destroy the Covenant space station Unyielding Hierophant and associated armada of over 500 warships in the Tau Ceti system prior to the Covenant's invasion of Earth.
The Battle of Installation 04 was an engagement between the UNSC Pillar of Autumn and the Covenant Fleet of Particular Justice on and around the Forerunner megastructure known as Installation 04, or Alpha Halo, in the Soell system.
The Battle for Earth was a large-scale space, air, and ground battle between the invading Covenant forces and the UNSC Home Fleet on and around Earth at the end of 2552.
The Skirmish on Mona Lisa was a minor conflict that occurred in the debris field of Installation 04 in the Soell system aboard the prison ship Mona Lisa between UNSC forces and an outbreak of the Flood on October 25th, 2552.
The Onyx Conflict was a major engagement between UNSC, Covenant, and Forerunner forces on and around the planet of Onyx in the Zeta Doradus system in October and November 2552.
The Battle of Installation 05 was an engagement between the Covenant forces, including those that fled the Battle for Earth, High Charity, and the Second Fleet of Homogeneous Clarity, and the UNSC-allied forces, including the UNSC In Amber Clad led by Miranda Keyes, and the Fleet of Retribution led by the Arbiter Thel 'Vadam.
The Battle of Installation 00 was a major conflict between the forces stationed aboard the UNSC Forward Unto Dawn and Arbiter Thel 'Vadam's Fleet of Retribution, and the Covenant fleet loyal to the Prophet of Truth.
Operation: SUNSPEAR was a mission to infiltrate Covenant space and destroy a major population center as an act of revenge for the Fall of Reach at the end of 2552.
At the start of the Covenant in 851 BCE, a group of Sangheili who did not agree with the peace being formed with the San'Shyuum, formed around their leader Ussa 'Xellus and escaped to a previously unknown Forerunner construct known as Shield World 0673.
The Blooding Years is the Sangheili term for the civil war that raged for five years on Sanghelios and throughout Sangheili-occupied territories following the end of the Human-Covenant War and disappearance of the San’Shyuum.
The Voi Memorial was erected in March 2553, marking the end of the Human-Covenant War and to remember all who were lost during the conflict.
The Siege at Kolaar was an attack on Arbiter Thel 'Vadam and his forces by Avu Med 'Telcam and the Servants of the Abiding Truth in the first major conflict of the Sangheili civil war.
The Skirmish on Pious Inquisitor was a small battle that took place between ONI intel unit Kilo-Five and Kig-Yar pirates on the CCS-class battlecruiser Pious Inquisitor in the Shaps system in April 2553.
Operation: JOVIAN WHISTLE was an operation executed by the UNSC 717th Xeno-Materials Exploitation Battalion to recover a Forerunner ancilla on the human colony world of Gao in the Cordoba system in the early summer 2553.
The Attack on Rahnelo was an unprovoked attack by the San'Shyuum Prelate Tem'Bhetek, directed by the former Covenant Minister of Preparation Boru'a'Neem, on the Sangheili colony world of Rahnelo towards the end of 2553.
The Ambush at Duraan was the second part of the prelate Tem'Bhetek's plan to lure in the Shadow of Intent, capture the ship, and kill Rtas 'Vadum.
The Battle of the Prototype Halo Installation was a conflict between Tem'Bhetek, the former Covenant Minister of Preparation Boru'a'Neem, and the Shadow of Intent crew including Rtas 'Vadum and Tul 'Juran.
Operation: RETRIBUTION was an Office of Naval Intelligence mission headed by operative Veta Lopis and her Ferret team to investigate the murder of Vice Admiral Graselyn Tuwa and the kidnapping of her family members on December 6th, 2553.
The Draco III Rebellion was an insurrectionist rebellion led by United Rebel Front leader Captain Ingridson in the city of New Albany on the colony world of Draco III in January 2554.
The Spartan Training Station Bombing was a terrorist attack on an orbital Spartan training facility by the United Rebel Front on March 29th, 2554.
The Return to Installation 00 was an Office of Naval Intelligence mission undertaken by the UNSC Rubicon to return to the Ark following the Battle of Installation 00 and investigate the status of the facility in August 2554.
Operation: FAR STORM was a joint UNSC and Swords of Sanghelios mission to reactivate the Portal at Voi and travel back to Installation 00 after discovering the Halo array was counting down to activation in March 2555.
The Invasion of Earth was an attempt by the monitor of Installation 00 to harvest the Earth for resources to repair the Ark when the Portal at Voi was reopened in March of 2555.
Operation: COALPEPPER was an ONI and Spartan operation to rescue Sadie Endesha and the Huragok Quick to Adjust to whom she was assigned from the United Rebel Front on the moon of Talitsa in the Sverdlovsk system in August 2555.
Sometime in January 2557, Rion Forge, a post-war salvager, and her ship the Ace of Spades, discover the location of what was left of the Etran Harborage after the destruction of the shield world during the events of the Battle of the Etran Harborage in 2531.
Following discovery of the last known location of the UNSC Spirit of Fire from the Battle of the Etran Harborage, the Office of Naval Intelligence sent the UNSC Taurokado to investigate the system for any information regarding the whereabouts of the lost UNSC warship.
The Mission to Mount Kilimanjaro was a trek undertaken by 343 Guilty Spark, Rion Forge, and the crew of the Ace of Spades to find the Librarian and, in the case of Spark, gain access to the Domain in September 2557.
~125,000 BCE
Around 125,000 BCE, the Forerunners built the crown jewel of their civilization, an artificial world that served as the center of all Forerunner governance, Maethrillian.
1342 CE
In 1342, Covenant ships arrived in the Y’Deio system, the home system of the Kig-Yar, finding a species with a penchant for piracy.
1112 CE
The Yanme’e were discovered by the Covenant during their search for Forerunner artifacts in 1112, sparking a short but violent conflict that eventually ended in the incorporation of the Yanme’e into the Covenant.
~500 Mya
Sometime long before the time of the Forerunners, the Precursors created the Domain, a repository of all knowledge in the universe. The exact date is unknown, and while some sources say it was created 500 million years ago, others say it has existed for billions of years.
~15 Mya
Around fifteen million years ago, the Forerunner race was created by the Precursors in an effort to make a new species that could assume the Mantle of Responsibility.
~10 Mya
Ten million years ago, the Precursors, the species that populated the galaxy with intelligent life including Forerunners, determined the Forerunners were a failed experiment and decided to remove them from the Milky Way galaxy.
~107,445 BCE
The birth of the Flood is actually a series of events that can be traced to a time period around 10,000 years prior to the firing of the Halo Array in 97,445 BCE.
~107,445 BCE - 106,445 BCE
After the emergence of the Flood on ancient human worlds around 107,445 BCE, human civilization was desperate to expand their territory away from Flood-controlled regions of space. As part of this expansion, humans clashed with Forerunner-populated worlds, sparking a war between the two species.
~106,538 BCE
Sometime prior to the end of the Human-Forerunner Wars, ancient humans discovered a Precursor stasis chamber containing a creature they called the Primordial. The creature, along with the stasis chamber, was taken to Charum Hakkor where is was interrogated, teaching the humans on the origins of the Flood.
~106,498 BCE - 106,445 BCE
The Battle of Charum Hakkor was one of the final battles of the Human-Forerunner Wars and also one of the largest, spanning over fifty years and likely consuming millions of lives.
~98,445 BCE
After losing political power to the Master Builder and the entire Builder rate following the end of the Human-Forerunner Wars, the Didact placed himself in exile within a cryptum on Nomdagro, which was later moved to Erde-Tyrene.
~98,395 BCE
The end of the Human-Forerunner War, along with the political fight afterwards that led to the Exile of the Didact, spurred much debate within Forerunner leadership about the right course of action to defend civilization and the galaxy against the Flood, should they return.
~97,745 BCE
Around 97,745 BCE, nearly nine-thousand years since the Flood disappeared from the galaxy during the Human-Forerunner Wars and three-hundred years before the Great Purification, the Flood were first observed at the edges of the galaxy on the planet Seaward, a Forerunner colony world.
~97,745 BCE - 97,445 BCE
The Forerunner-Flood War was a military engagement between the Forerunner species and the Flood that took place over approximately three-hundred years from 97,745 BCE until 97,445 BCE.
~97,495 BCE
The release of the Primordial was an unintended consequence of the test-firing of a Senescent Halo, Installation 07, by the Master Builder and Mendicant Bias in the Charum Hakkor system during the Forerunner-Flood War, approximately fifty years prior to the end of the war and the Great Purification.
~97,455 BCE
Following the Didact’s self-imposed exile one thousand years prior after losing the political battle over the Forerunner defense plan against the Flood, the Didact is resurrected from his cryptum on Erde-Tyrene by Forerunner Manipular Bornstellar Makes Eternal Lasting, and humans Chakas and Riser.
~97,455 BCE
The Battle of Janjur Qom was a brief conflict between the San’shyuum and Forerunners on the quarantined San’shyuum homeworld of Janjur Qom several years prior to the firing of the Halo Array during the Great Purification in 97,445 BCE.
~97,455 BCE
After the Revival of the Didact and his exploration of the Charum Hakkor system with fellow Forerunner Bornstellar Makes Eternal Lasting and humans Riser and Chakas, the Didact and crew traveled to the quarantined San’shyuum homeworld of Janjur Qom to try and unlock more memories in their quest for understanding.
~97,454 BCE
The Fate of Maethrillian was a large-scale but brief battle between the Forerunners and the Halo Array under command of Mendicant Bias several years prior to the firing of the halos during the Great Purification in 97,445 BCE.
~97,454 BCE
In the aftermath of the Fate of Maethrillian and destruction of the Forerunner ecumene, Zeta Halo implemented it’s security measure designed to prevent the ring from falling into enemy hands and performed a slipspace jump into another system and put itself on a collision course with a nearby planet.
~97,450 BCE
After the Master Builder captured the Didact over Janjur Qom, he decided to dispose of the Didact on a derelict Forerunner ship with a handful of other political prisoners in an area of Flood-controlled space known as a Burn.
~97,445 BCE
The Battle of the Greater Ark was one of the final battles of the Forerunner-Flood War and saw the decimation of almost all remaining Forerunner forces just prior to the firing of the Halo Array during the Great Purification in 97,445 BCE.
~97,445 BCE
The behavior of the Ur-Didact following his encounter with a Gravemind and return to the Forerunner civilization became more erratic and harder for the IsoDidact and Librarian to cope with as the Forerunner-Flood War continued.
~97,445 BCE
The Great Purification was the final event of the Forerunner-Flood War, purging the entire Milky Way galaxy of all sentient life, including Forerunners, the Flood, and any other species that may have survived the Flood infestation.
~97,300 BCE
Over one-hundred years after the Great Purification, the few Forerunners remaining on the Lesser Ark became aware that the firing of the Halo Array may have had a detrimental effect on the Domain, and proceeded to the former Forerunner capital of Maethrillian to attempt to restore it.
2200 BCE - 2100 BCE
The War of Wills was a fierce and prolonged conflict between two factions of the San’Shyuum: The Stoics who wanted to worship Forerunner technology but never use it, and the Reformists who wanted to take advantage of the incredible Forerunner artifacts around the galaxy.
938 BCE - 852 BCE
The War of Beginnings was an eighty-six year conflict between the San’Shyuum Reformists who escaped Janjur Qom after the War of Wills and the Sangheili species between 938 and 852 BCE.
860 BCE
The Skirmish of the Planet of Blue and Red was a conflict between the San’Shyuum and Sangheili during the War of Beginnings in 860 BCE.
852 BCE
The Writ of Union was a declaration of peace between the San’Shyuum and the Sangheili, as well as the formation of the Covenant, signed by both species in 852 BCE.
852 BCE - 791 BCE
The Writ of Union not only formed an alliance between the Sangheili and the San’Shyuum, but also commissioned the construction of a great holy city of the Covenant, known as High Charity.
