A timeline of all major events in the Halo universe from the time of the Forerunners through the rule of the Created.
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.
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.
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.
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.
Operation: WARM BLANKET was an operation to recover Doctor Halsey from the Covenant after her capture during the Battle of Miridem in 2544.
Spartan-III Gamma Company was the last of three Spartan-III companies to be recruited, trained, and put into service.
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.
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 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 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.
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.
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: 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 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: 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.
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 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.
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 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.
ONI agent Lieutenant Parisa, is sent on a mission to deliver an encryption key to John-117 behind enemy lines prior to the Battle of Installation 07.
