The Halo timeline spans nearly four centuries of human expansion, conflict, and survival across the galaxy. It begins in the twenty-second century with the founding of the United Nations Space Command, the political and military body that will govern humanity's reach into space. Early colonisation proceeds rapidly as Slipspace technology opens interstellar travel, but the outer colonies grow restless under Earth's authority. By the late twenty-fifth century, armed insurrection is spreading through the fringes of human space, forcing the UNSC to develop new military responses including the classified SPARTAN-II programme, which produces augmented supersoldiers of extraordinary capability.
Everything changes in 2525 when the Covenant, a powerful theocratic alliance of alien species, makes contact with humanity at the colony world of Harvest. The encounter is not peaceful. The Covenant declare humanity an affront to their religion and launch a systematic campaign to destroy every human world they find. What follows is nearly three decades of devastating war. Entire colonies are glassed from orbit. Billions die. The UNSC fights a losing defensive action across countless systems, culminating in the fall of Reach in August 2552, the loss of humanity's most important military world outside Earth itself.
In the weeks that follow, a single vessel stumbles upon an ancient ringworld designated Installation 04. This discovery pulls the surviving crew into a conflict far older than the Covenant War, involving the Flood, a parasitic organism capable of consuming all life, and the Forerunners, a vanished civilisation that built the rings as a last resort against extinction. From that moment, the Halo timeline becomes a record of escalating revelations: about the nature of the rings, the identity of the Reclaimers, and the threat posed by intelligences both ancient and newly awakened.
The United Nations Space Command is established as humanity begins expanding beyond Earth. It becomes the primary military and governmental authority overseeing human colonisation across the galaxy.
Open record →Slipspace technology enables faster-than-light travel and opens the galaxy to human colonisation. It is the technological foundation on which the entire era of expansion is built.
Open record →Armed resistance against UNSC authority breaks out in the Outer Colonies. The Insurrection forces the UNSC to divert significant military resources away from exploration and toward internal security.
Open record →A classified programme begins to produce augmented supersoldiers from a pool of candidates identified and conscripted in childhood. The Spartans will become humanity's most capable warriors in the conflicts ahead.
Open record →The Covenant arrive at the colony world of Harvest and declare humanity an affront to their religious beliefs. The encounter marks the beginning of a war that will reshape human civilisation.
Open record →The Covenant assault and destroy Reach, humanity's most strategically vital world outside Earth. The loss is catastrophic and effectively ends any hope of a conventional military victory against the Covenant.
Open record →The Pillar of Autumn, fleeing Reach, makes a blind jump and arrives at an ancient ringworld. The discovery of Installation 04 pulls the surviving crew into a conflict far older than the Covenant War.
Open record →Three days after its discovery, Installation 04 is destroyed to prevent the Flood from escaping into the wider galaxy. The action saves countless lives but leaves the survivors stranded far from human space.
Open record →A Covenant fleet arrives at Earth. For the first time, the war comes directly to humanity's home world. The battle marks a turning point as the Covenant's true objective begins to come into focus.
Open record →A political and religious rupture splits the Covenant from within. Two of its major species turn against each other, fundamentally changing the nature of the war and creating unexpected opportunities for humanity.
Open record →The war reaches its conclusion at the Ark, the installation responsible for building and controlling the Halo rings. The outcome determines the fate of both the Flood and the surviving forces on all sides.
Open record →In the aftermath of the war, the UNSC commissions its most advanced warship. The Infinity represents humanity's commitment to rebuilding its military capability and continuing exploration in a changed galaxy.
Open record →A Forerunner military commander, imprisoned for millennia, is encountered inside a Forerunner shield world. His reawakening introduces a threat with technology and capabilities far beyond anything the Covenant possessed.
Open record →An artificial intelligence seizes control of Forerunner Guardian constructs and issues an ultimatum to the galaxy. The Created represent a new kind of threat, one that operates from within humanity's own technological infrastructure.
Open record →On Installation 07, the Master Chief reawakens after a period of isolation. The Banished, a powerful mercenary faction, have seized control of the ring, and a new conflict begins on the surface of a Halo installation with deep connections to the Forerunner past.
Open record →Q: What is the Halo timeline in order?
UNSC founded (2163) → Slipspace discovered (2291) → Insurrection begins (2494) → SPARTAN-II program begins (2517) → Covenant first contact at Harvest (2525) → Fall of Reach (2552) → Pillar of Autumn arrives at Installation 04 (2552) → Installation 04 destroyed (2552) → Battle for Earth begins (2552) → Great Schism divides the Covenant (2552) → Battle of the Ark (2552) → UNSC Infinity commissioned (2553) → First contact with the Didact (2557) → Rise of Cortana and the Created (2558) → Reawakening on Zeta Halo (2560).
Q: When does the Covenant War start in Halo?
The Covenant War begins on 3 February 2525 when the Covenant make first contact with humanity at Harvest. They declare humanity an affront to their religion and begin a campaign of systematic destruction of human worlds that lasts nearly three decades.
Q: When does Halo: Combat Evolved take place?
Halo: Combat Evolved takes place in September 2552. The Pillar of Autumn arrives at Installation 04 on 19 September 2552, and the ring is destroyed on 22 September 2552 after three days of combat against both the Covenant and the Flood.
Q: When does Halo Infinite take place?
Halo Infinite takes place on 28 May 2560 on Zeta Halo, also known as Installation 07. The Master Chief reawakens on the ring and confronts the Banished, a powerful mercenary faction that has seized control of the installation.