A timeline of all major events in the Halo universe from the time of the Forerunners through the rule of the Created.
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.
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 Battle of Alpha Corvi II was a battle between the UNSC and the Covenant forces in the Alpha Corvi system on December 3rd, 2525.
The Battle of Bliss was a Covenant attack on the outer colony world of Bliss on February 13th, 2526.
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.
WINTER CONTINGENCY was a UNSC emergency plan directive that was declared whenever it was determined the Covenant had learned the location of a colony world.
The Battle of Circinius IV was a Covenant attack on the planet Circinius IV and Corbulo Military Academy located on the planet.
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 Battle of XI Boötis A was a naval battle during the early portions of the Human-Covenant War.
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.
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.
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.
Operation: GREY VEIL was an Office of Naval Intelligence mission to assassinate a Covenant Prophet on the planet Heian sometime in 2541.
The Battle for Alluvion was a major conflict in the Human-Covenant War that took place in the Bhaakto system some time in 2542.
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.
Operation: WARM BLANKET was an operation to recover Doctor Halsey from the Covenant after her capture during the Battle of Miridem in 2544.
Operation: IRON FIST was a military operation on the colony of Miridem after the Battle of Miridem in 2544 and prior to the colony's glassing.
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 New Llanelli was an engagement between UNSC and Covenant forces on the colony world of New Llanelli in the Brunel system, sometime in 2546.
The Battle of Sargasso was a conflict between invading Covenant and defending UNSC forces on the colony of Sargasso on September 21st, 2546.
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 Battle of Meridian was a three-year conflict between the Covenant and UNSC forces on and around the colony world of Meridian, a moon around Hestia V in the Hestia system, between 2548 and 2551.
The Siege of Paris IV was a major battle between the UNSC and Covenant forces on and around the colony of Paris IV in the Paris system in 2549.
The Algolis Invasion was a Covenant attack on the human colony world of Algolis in the Algol system sometime between 2548 and 2552.
The Fall of Arcadia, also known as the Second Fall of Arcadia, was a Covenant invasion and subsequent loss of the colony world of Arcadia in the Procyon system on September 9th 2549.
The Battle of Gamma Pavonis VII was a small skirmish over the planet of Gamma Pavonis VII in the Gamma Pavonis system in early 2550.
The Glassing of Minab was a Covenant attack on the outer colony world of Minab in 2550.
The Defense of Concord was an attack by an unknown Covenant force on the colony of Concord, sometime in 2551.
The Battle of Ballast was a conflict between Covenant and UNSC forces on and around the colony of Ballast in 2551 or 2552.
Operation: FIRESIDE was an ODST mission to investigate a distress call sent by civilians on the colony world of Ariel, which had come under attack by Covenant forces days earlier in late December 2551 or early January 2552.
The Battle of Fumirole was a conflict between Covenant and UNSC forces on the colony Fumirole, April 22nd, 2552.
The Battle of Beta Eridani was a Covenant assault on UNSC forces in the Beta Eridani system, shortly before the summer in 2552.
The Massacre of Troy was a Covenant invasion of the colony of Troy in the Hellespont system approximately five months prior to the Battle for Earth.
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 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 Raid on Verge was a covert mission undertaken by Spartan-II Black Team to infiltrate and destroy a Covenant mining and refinery operation on the recently invaded former colony of Verge towards the end of July 2552.
The Battle of Line Installation 1-4 was a conflict on Line Installation 1-4, a Forerunner defensive facility that was part of the Jat-Krula, the Forerunner's version of the Maginot Line during the Forerunner-Flood war in August 2552.
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 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.
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.
