Halo Timeline

2160-2200	This period in human history was marked by a series of brutal conflicts between various governments and factions in our Solar System. Conflicts of particular historical importance included the Jovian Moons Campaign, The Rain Forest Wars, and a series of clashes on Mars. As overpopulation and political unrest on Earth increased, a number of new political movements formed. The most noteworthy dissident movements of the period were the "Koslovics" and the "Frieden" movement. The Koslovics—supporters of neo-Communist hardliner Vladimir Koslov—sought a return to the glory days of Communism and the elimination of corporate and capitalist influence, particularly in orbital facilities and offworld colonies. The Frieden movement was a resurgence of fascism, springing from anti-Koslovic sentiment that had taken root in the Jovian colonies (largely backed by Unified German Republic corporations, frequent targets of Koslovic "workers' crusades"). "Frieden" literally means "peace"-in this case, they believed that peace could be achieved only once the "oppressors on Terra Firma" were eliminated.
2160	March-June: The Jovian Moons Campaign began. Jovian secessionist attacks on United Nations Colonial Advisors on the moon Io led to three months of fighting between the Earth military and Jovian "Frieden" forces. Though this was not the first armed conflict in our Solar System, it was easily one of the bloodiest, and is generally considered to be the spark of increased friction and militarization that followed. The Jovian Moons Campaign escalated tensions, as Earth's national governments-many of which sponsored colonies within the system-began fighting proxy wars off-planet. As these proxy wars continued, tensions on Earth mounted, leading to a number of armed conflicts on Earth itself.
2162	The Rain Forest Wars: Armed conflict ripped through South America, as Koslovic, Frieden, and UN forces all clashed over ideological differences, sparking additional conflicts off-planet.
2163	December: In a conflict that stemmed from the Rain Forest Wars, the three primary Earth factions clashed again, this time on Mars. A series of lightning strikes against Koslovic forces near the Argyre Planitia marked the first extra-terrestrial deployment of Marines. The campaign was an unqualified success. As a result, future military doctrine favored large contingents of Marines for ground assaults and ship-boarding actions.
2164	UN-sponsored military forces begin a pattern of massive buildups, culminating in the first real interplanetary war. After the successful Marine deployment on Mars, recruitment drives and propaganda tactics strongly bolster UNSC (UN Space Command) forces. UN forces defeat Koslovic (supporters of rabid Communist hard-liner Vladimir Koslov) and Frieden (a resurgence of fascism) forces on Earth, then begin a systematic and dedicated drive to crush their remnants on the various planets they hold throughout the system. At the conclusion, Frieden and Koslovic forces are defeated, in the face of a massive, unified and very powerful UN military.
2170	A unified Earth government was formed in the wake of the conflicts of 216. Now, the victors were forced to deal with a less obvious but equally serious threat: overpopulation and a massive military that had no enemy to fight. In the postwar period there were massive population surges and the overpopulation, coupled with the destruction and famine bred by the Rain Forest Wars, threatened to destabilize the economy.
2291	A team of researchers, physicists, and mathematicians working in secret developed the Shaw-Fujikawa Translight Engine, a practical means of propelling spacecraft across vast interstellar distances. This new engine allowed ships to tunnel into "the Slipstream" (also called "Slipspace"). Slipspace is a domain with alternate physical laws, allowing faster-than-light travel without relativistic side-effects. Faster-than-light travel is not instantaneous; "short" jumps routinely take up to two months, and "long" jumps can last six months or more. The SFTE generated a resonance field, which when coupled with the unusual physics of the Slipstream, allowed for dramatically shorter transit times between stars; however, scientists noted an odd "flexibility" to temporal flow while inside the Slipstream. Though no human scientist is sure why travel time between stars is not constant, many theorize that there are "eddies" or "currents" within the Slipstream-there is generally a five to ten percent variance in travel times between stars. This temporal inconsistency has given military tacticians and strategists fits-hampering many coordinated attacks.
2310	The Earth government unveils the first in a line of colony ships; given conditions on Earth are deteriorating in the face of overpopulation, hitching a ride out to a colony becomes a highly attractive option. Additionally, the Earth government plans to attach military personnel to each colony, to help better utilize the massive (and expensive) standing fleets. Because FTL travel is still fairly new and expensive, colonists and military personnel face a stringent regimen of physical and mental testing. In theory, only the best-qualified citizens and soldiers are allowed to colonize "nearby" worlds. This is the birth of the Inner Colonies; typically Inner Colonials are-later in the timeline-considered the elite, the best and brightest.
2362 Jan 1	The Odyssey is launched. The lead ship in the colony vessels, the Odyssey-laden with troops and terra forming gear-spearheads the colonization of a new world. This sparked the first wave of human expansion beyond the confines of the Solar System.
2390	The colonization of the Inner Colonies was fully underway. There were 210 human-occupied worlds in various stages of terraforming, and the population burden across human-controlled space was largely stabilized.
2490	Expansion continued at a rapid pace, and by 2490 human space encompassed more than 800 worlds throughout the Orion Arm of the Milky Way (ranging from fairly well-tamed planetary strongholds to tiny hinterland settlements). Outward expansion continued, and the Inner Colonies become a political and economic stronghold, though they relied heavily on raw materials supplied by the Outer Colonies. During this period, the planet Reach (orbiting Epsilon Eridani, right on Earth's metaphorical doorstep) became the UNSC's primary Naval yard and training academy. Reach was a major producer of warships and colony vessels, as well as a training ground for covert operatives and Special Forces.
2494	First rebel insurrection in Eridanus system.
2496	The Eridanus insurrection is defeated by UNSC forces.
2510	The structural system for the Pillar of Autumn is designed by Dr. Robert McLees at the Reyes-McLees Shipyards over Mars.
2512	A geological survey team on Sigma Octanus IV finds rocks with odd compositions - these were introduced from meteor impacts roughly 60,000 years ago.
2513	Second rebel insurrection in Eridanus system, led by Colonel Robert Watts, is suppressed by the UNSC in operation TREBUCHET. Watts is driven into the local asteroid belt.
2517 Aug 17	Dr. Halsey and Lieutenant Keyes meet 6-year-old John on a playground in Elysium City, Eridanus-2.
2517 Sep 23	Project SPARTAN II begins on Reach with 75 conscripts. Project SPARTAN is an attempt to develop an effective, surgical military team to relieve political tensions and circumvent civil war.
2519 Jul 12	John makes squad leader.
2523 Jul 14	Spartan Training exercise: Capture the Flag against Tango Company.
2525 Feb 3	Contact with Harvest, an outer colony, is lost shortly after the colony itself had made contact with an unknown object. The Colonial Military Administration sends the scout ship Argo to investigate.
2525 Apr 20	The Argo arrives in-system and makes one confirmation transmission. No further reports are received.
2525 Mar 9	The Spartans undergo a radical series of biological, neurological, and physiological alterations. 31 die, 12 are permanently disabled, and 32 successfully adapt.
2525 Sep 12	The Spartans first "official" mission, to infiltrate the rebel base on Eridanus to capture the rebel leader, Colonel Robert Watts, is successful.
2525 Oct 7	A UNSC battle group consisting of one Destroyer (Heracles, Captain Veredi) and two Frigates (Arabia and Vostok) enters the Harvest system and discovers that everything on the planet has been completely incinerated and the surface melted down to glass. In orbit around the remains of the colony world is a single alien ship, which proceeded to attack the battle group, destroying both Arabia and Vostok and badly damaging the Heracles. Intercepted communications identify the enemy as The Covenant. The message "Your destruction is the will of the Gods... and we are their instrument" is broadcast in UNSC language.
2525 Nov 1	Vice Admiral Preston Cole mobilizes the largest fleet in human history to retake Harvest.
2525 Nov 2	The Spartans learn of the attack of the Covenant at Harvest and Project MJOLNIR commences. CPO Mendez leaves to train next group of Spartans.
2525 Nov 27	Project MJOLNIR, a comprehensive package of scientifically enhanced armor, custom-tailored to the biologically augmented Spartans, is introduced to John and his squad at the UNSC Damascus Materials Testing Facility, on the planet Chi Ceti-4. The Spartans (now decked out in Mjolnir armor) destroy a Covenant ship by carrying a nuke onboard, inside the energy shield.
2531	Cole's war fleet engages the alien warship responsible for the decimation of the colony, scoring a victory (though the battle cost Cole two-thirds of his battle group). Only a last minute tactical inspiration turned the tide of battle. After returning to Earth, Cole-promoted to Admiral-learns that a number of outlying colonies have been destroyed, leaving behind no survivors. Cole begins to move his fleet around, trying to intercept the invaders. Ground and ship-to-ship battles begin in earnest, raging throughout the Outer Colonies. During one ground engagement, Human forces capture one of the aliens. Before succumbing to his wounds, interrogators learn that the aliens refer to themselves as "the Covenant" (roughly translated).
2535	In the course of four short years, Cole's forces are hammered, despite his excellent leadership and tactical brilliance. It is simply a matter of being outgunned; Covenant kill ratios tend to top four to one in ship-to-ship combat. By 2535, virtually all of the Outer Colony worlds have been destroyed by the Covenant. The "Cole Protocol" is established by military order: all human vessels must ensure that Covenant forces do not find Earth. Human ships must-when forced to withdraw-not move on to an Earth bound vector, even if that means jumping without proper navigational calculations. If blind jumps are not possible, the ship's captain must order self-destruction if capture is imminent. In addition, it is also imperative that the powerful ship A.I. data cores not fall into Covenant hands, so part of this protocol involves either the removal or destruction of the ship's A.I. in extreme situations.
2535 Feb 12	Jericho VII in the Lambda Serpentis system falls. Master Chief, on board the UNSC Destroyer Resolute under Captain de Blanc, is allowed to view as the Covenant fleet glasses the planet.
2536	Covenant forces begin to swarm into the Inner Colonies. For several years the war falls into a pattern: humans win isolated battles, typically during ground operations, but at a horrible cost. In space combat, the humans are losing at a precipitous rate, and one by one, the colonies fall.
2550	The Pillar of Autumn is refit to serve near Zeta Doradus.
2552 Jul 17	A Covenant fleet is discovered by Ensign William Lovell on UNSC Remote Scanning Outpost Archimedes, entering the Sigma Octanus system. Commander Keyes, on board the UNSC Destroyer Iroquois, takes on 4 medium-tonnage Covenant craft (two frigates, one destroyer, one carrier), and destroys 3 of them in what becomes known as the 'Keyes Loop'. The Carrier heads to Sigma Octanus IV and drops Covenant troops, invading the city of Cote D'Azur. Keyes is promoted to Captain by Admiral Stanforth.
2552 Jul 18	The Spartans and the Marines engage Covenant forces on the ground, eventually nuking Cote D'Azur and most of the Covenant invasion force (but very few humans), while 4 dozen UNSC ships engage 20 Covenant craft. Seven human craft survive. The Iroquois destroys a stealth ship receiving an encrypted transmission from the surface. Once this ship is destroyed, the 7 surviving Covenant ships break off and flee. The Iroquois heads back to Reach for debriefing. A Covenant tracker attaches itself, unseen, to the Iroquois' hull.
2552 Aug 12	The Master Chief is debriefed by ONI at Camp Hathcock, Reach, on the events of Cote D'Azur.
2552 Aug 25	The Pillar of Autumn is chosen by Dr. Halsey and Cortana (with Keyes as Captain) to handle a secret mission that Dr. Halsey is planning.
2552 Aug 27	John rejoins the remaining Spartans (except for three that are otherwise engaged) in the FLEETCOM Military Complex on Reach, where they learn of their next mission: To acquire a Covenant vessel, navigate to the Covenant home world, and return with captured Covenant leadership.
2552 Aug 29	The Master Chief gets a neural interface upgrade and new armor with built-in Covenant shield technology. He is also introduced to Cortana, an A.I. created from Dr. Halsey's own neural patterns.
2552 Aug 30	Cortana gets revenge on Colonel Ackerson, part of ONI's Special Warfare branch, for attempting to eliminate Cortana and Master Chief - she gets him transferred to the front. Bypassing several other colonies, the Covenant arrive at Reach and begin what has become all too familiar to the embattled Human forces: the destruction of the planet.
2552 Aug 30	The Spartans are divided into two teams: Red and Blue. John and the rest of Blue team (Linda and James), while on an orbital mission to ensure that a NAV database stays out of Covenant hands, end up onboard the Pillar of Autumn when she jumps away from the Reach system to evade Covenant forces. James is lost and Linda is mortally wounded, and the subsequent mission on Halo is left to the Master Chief to complete. The Covenant take the surface of Reach, and Red team splits, one group to retrieve Admiral Whitcomb, while the rest hole up in ONI's Castle Base underground facility with Dr. Halsey. The Spartans receive parts of a MJOLNIR Mark V upgrade and new weapons, while Dr. Halsey learns of Colonel Ackerson's mysterious plans, plans that seem to involve "her" Spartans.
2552 Sep 4	Lieutenant Wagner returns to Earth and reports on the evident destruction of Reach to Colonel Ackerson, Admiral Hood, and General Strauss at an ONI facility in Sydney, Australia.
2552 Sep 7	The Time/Date Record Anomaly of Sep 23, 2552 most likely rejoins the timeline here. Dr. Halsey and members of Red team discover an enigmatic shard in an ancient installation below the ONI facility. Blue team joins with team Gamma to retrieve Admiral Whitcomb, and rejoin the rest of Red team who have been besieged by the Covenant, who apparently revere the artifact that the humans have found.
Unknown	The remaining Spartans, Admiral Whitcomb, Dr. Halsey, Sgt. Johnson, Lieutenant Haverson, Warrant Officer Polaski, and Corporal Locklear jump to Slipspace on board the Covenant/Human hybrid ship Gettysburg-Ascendant Justice, and discover that the shard seems to have the ability to bend both space and time.
2552 Sep 12	The Gettysburg/Ascendant Justice arrives for refit and provisioning in Eridanus system and meets with the rebels under Governor Jiles. Dr. Halsey sedates Spartan 087, Kelly, and absconds with her on Governor Jiles ship, a Chiroptera-class vessel, the smallest UNSC classification that contains an SFTE. Before she goes, she gives the alien artifact to Corporal Locklear, with implicit instructions to destroy it.
2552 Sep 13	Admiral Whitcomb and Lieutenant Haverson destroy the majority of the surrounding Covenant fleet by detonating the Unyielding Hierophant. John, Linda, Will, and Fred, the last known remaining Spartans, along with Sgt. Johnson, and, of course, Cortana, depart for Earth to warn of the impending Covenant invasion.
2552 Sep 19	The Pillar Of Autumn arrives at Halo.
2552 Sep 22	The Master Chief and Cortana, onboard a Longsword in the debris field of the destroyed Halo, find one remaining Pelican containing Sgt. Johnson, Lieutenant Haverson, Warrant Officer Polaski, Corporal Locklear, and a set of cryotubes containing Spartan 058, Linda.
2552 Sep 23	The Master Chief, Cortana, Linda, Polaski, Sgt. Johnson, Haverson, and Locklear depart for Reach via Slipspace aboard the Covenant Flagship Ascendant Justice, captured near the Halo debris field. A Time/Date Record Anomaly continues from this point in the narrative, resolved above on Sep 7, 2552.