A timeline of all major events in the Halo universe from the time of the Forerunners through the rule of the Created.
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 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.
The outer colony world of Harvest, one of the youngest human colonies, was settled sometime in 2468.
In 2491, the Office of Naval Intelligence re-instituted the Orion Project, an attempt to create engineered super-soldiers to boost combat effectiveness.
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.
The Battle for Arcadia was a battle for the colony Arcadia in the Procyon system, which occurred in the immediate aftermath of the Harvest Campaign.
The Battle of the Etran Harborage was a battle between the UNSC Spirit of Fire and Covenant forces lead by Arbiter Ripa 'Moramee on Shield World 0459, also known as the Etran Harborage.
Operation: PROMETHEUS was an assault on a Covenant shipyard located on and around asteroid K7-49 by Spartan-III Alpha Company.
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.
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 Battle of Sigma Octanus IV was a large-scale space and ground battle between UNSC and Covenant forces in the Sigma Octanus system in July 2552.
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 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 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 Great Schism was a conflict between the forces loyal to the Covenant, led mostly by the Jiralhanae, and the Sangheili, beginning on November 3rd, 2552 and continuing off and on until the Rule of the Created in 2558.
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.
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 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.
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 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.
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.
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.
The Mission to Alpha Shard was a joint ONI and Sedran Colonial Guard mission to secure and eliminate the source of the bio-weapon used in the Sedra City Mall Bombing in February 2556.
The Battle of Requiem was a conflict between former Covenant forces under the command of Jul 'Mdama, UNSC forces from the UNSC Infinity and Forward unto Dawn, and Promethean forces under command of the Ur-Didact on Forerunner Shield World 0001, also known as Requiem, in July 2557.
The New Phoenix Incident was an attack by the Ur-Didact on the Earth city of New Phoenix on July 25th, 2557 using the Composer that he had acquired from Ivanoff Station the day prior.
The Mission to Installation 03 was a UNSC operation to investigate the loss of contact with a science outpost and Spartan-II Black Team on Gamma Halo immediately following the New Phoenix Incident in July 2557.
The Requiem Campaign was a UNSC mission to return to Requiem, and take control of the shield world away from Jul 'Mdama and his Covenant remnants in February 2558, six months after the Battle of Requiem.
The Battle of Aktis IV was a conflict between the UNSC forces aboard the Infinity and the Covenant forces under command of Jul 'Mdama on the planet of Aktis IV in July 2558.
The Raising of the Guardians was a series of events involving the awakening and unearthing of Forerunner ships known as Guardians by Cortana in late October 2558.
The Battle of Genesis was an engagement between the UNSC, Promethean forces under command of Cortana, and the remains of Jul 'Mdama's Covenant forces on the artificial Forerunner installation known as Genesis in October 2558.
The Second Battle of Meridian was a conflict between the colonists of Meridian funded by the Liang-Dortmund Corporation, the UNSC, and Prometheans under control of Cortana on October 25th, 2558.
The Battle of Sunaion was a battle between the Swords of Sanghelios led by Thel 'Vadam, their allies Fireteam Osiris led by Jameson Locke, the last of Jul 'Mdama's Covenant forces, and the Created forces led by the Warden Eternal in the state of Sunaion on the Sangheili homeworld of Sanghelios.
~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 - 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.
~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.
~97,445 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.
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.
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.
