A timeline of all major events in the Halo universe from the time of the Forerunners through the rule of the Created.
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.
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 Spartan-IV program was the third successful Spartan training program and the first since the end of the Human-Covenant War.
The Raid on UNSC Infinity was an attempted infiltration and commandeering of the UNSC Infinity by insurrectionist forces calling themselves the New Colonial Alliance in January 2553.
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-IV program was the third successful Spartan training program and the first since the end of the Human-Covenant War.
The Battle of Draetheus V was an attack by former Covenant forces under the command of Sangheili Zealot Merg Vol on the colony world of Draetheus V and its moon X50 sometime in 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.
The Sedra City Mall Bombing was a terrorist attack on the human colony world of Sedra in the Orrichon system by an unknown Sangheili terrorist organization in February 2556.
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 Mission to Cleyell was a UNSC mission to the colony world of Cleyell, which had recently been glassed by a fringe group of Covenant remnants sometime in 2556.
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 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 Battle of Installation 03 was a battle between the UNSC and Covenant remnant forces under command of Jul 'Mdama on Gamma Halo during and immediately following the New Phoenix Incident in July 2557.
The Raid on Ivanoff Station was an attack by the Ur-Didact and his ship Mantle's Approach on the Office of Naval Intelligence research facility Ivanoff Station nearby Halo Installation 03 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 Battle of New Phoenix was a military engagement between the UNSC and Covenant remnant forces under command of Jul 'Mdama in the city of New Phoenix on Earth, immediately after the New Phoenix Incident and the Battle of Installation 03 in July 2557.
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.
The Assassination of Avu Med 'Telcam was an assassination sanctioned by the Office of Naval Intelligence Section Three and carried out by SPARTAN-G059 on the leader of the Servants of the Abiding Truth on former colony world New Llanelli in the Brunel system in January 2558.
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 Ealen IV was an attack on peace negotiations between the Sangheili and Jiralhanae on Ealen IV in the Ealen system in March 2558.
The Ambush at Oth Lodon was an attempt by the New Colonial Alliance to destroy the UNSC Infinity and kill Admiral Hood after the failed assassination attempt at Ealen IV days earlier.
The Raid on the Biko Peace Talks was an attempted terrorist attack on peace talks between the Unified Earth Government and Sangheili on the colony world of Biko in March 2558.
Operation: WHISTLE STOP was a UNSC and ONI mission to recover a potential bio-weapon from a group of Sangheili and Kig-Yar pirates on the planet Ven-III in May 2558.
The Battle of Oban was a conflict between the UNSC and Covenant forces under command of Jul 'Mdama on the colony world of Oban in July 2558.
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 Carrow Conflict was a conflict between human, Sangheili, and Jiralhanae forces in the Joint Occupation Zone on the planet of Carrow in September 2558.
Operation: ATHENA was a covert UNSC mission to infiltrate the Song of Retribution, and retrieve the Janus Key from Jul 'Mdama and his Covenant remnant forces in September 2558.
The Battle of Kamchatka was a battle between Covenant remnant forces under the leadership of Jul 'Mdama, local Promethean forces under control of Cortana, and the UNSC in the form of Spartan-IV Fireteam Osiris on the planet of Kamchatka in October 2558.
Operation: BIRD IN HAND was a UNSC mission carried out by Spartan-II Blue Team to infiltrate and recover the Office of Naval Intelligence research vessel Argent Moon on October 23rd, 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 Nuusra was a battle between the remnants of Jul 'Mdama's Covenant forces, the Swords of Sanghelios, and Spartan-IV Fireteam Osiris in the sate of Nuusra on the continent Qivro on the Sangheili homeworld of Sanghelios on October 27th, 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.
The discovery of Bastion was the culmination of a series of events involving 343 Guilty Spark and Rion Forge that led to the discovery of the Librarian’s shield world.
The Battle of Cassidy III was a conflict between Spartan-IV fireteam Alpha-Nine, allied with United Rebel Front forces on Cassidy III, and the Promethean forces under command of the Created late in 2558.
The Second Ark Conflict was a battle between the UNSC forces aboard the Spirit of Fire and the Banished forces under command of Atriox on Installation 00 in 2559.
The Outbreak on Installation 00 was a brief encounter between Banished forces and the Flood on the surface of the Ark in and around the wreckage of the Covenant holy city High Charity.
Operation: WOLFE was a UNSC mission on the planet Reach in October 2559 to recover several cryobins from CASTLE Base under Menachite Mountain for Doctor Catherine Halsey.
The Battle of Epsilon Clarion was a conflict on the Ark between the Keepers of the One Freedom, the Covenant, and the Banished to activate the Halo Array in late 2559.
