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Historical Record
On 19 September 2552, the UNSC Pillar of Autumn emerges from Slipspace in the Soell system after escaping the destruction of Reach. The ship does not arrive in open safety or at a friendly rally point. Instead it finds itself near an immense ring shaped structure later designated Installation 04. This is the first direct human encounter with a Halo ring, and it happens under extreme pressure. The Autumn is damaged, pursued by Covenant forces, and carrying survivors from one of the worst defeats in human history. The ring itself dominates the scene immediately. It is impossible to mistake for a natural object, and its sheer scale makes clear that humanity has entered a setting shaped by a civilisation far older and more capable than anything known in the Covenant War.
The arrival is not a calm discovery mission. Covenant ships are already present, and a battle begins almost as soon as the Autumn reaches the ring. Captain Jacob Keyes and Cortana attempt to preserve what remains of the ship and crew, but the tactical situation deteriorates quickly. To prevent capture, the Autumn is brought down onto the ring in a controlled crash. Lifeboats and escape craft scatter personnel across the installation, leaving isolated pockets of marines, naval officers, and support staff to regroup on unfamiliar terrain. Master Chief enters the ring during this chaotic phase, and the human presence on Installation 04 begins not with survey teams or diplomats, but with stranded soldiers fighting for survival.
The first hours on the ring reveal a strange mixture of beauty and danger. Installation 04 has weather systems, varied landscapes, and immense internal architecture, yet almost nothing about it feels ordinary. Human survivors establish defensive positions and attempt rescue operations while Covenant troops search the surface and nearby structures. The ring quickly proves to be more than a battlefield. It is also a site of mystery, with obvious signs of artificial design and hidden systems whose purpose is not yet understood. Cortana and other human personnel begin piecing together the significance of the installation, but at this stage the central fact is simple. Humanity has stumbled into a place that the Covenant values deeply and that neither side fully understands.
The arrival at Installation 04 matters because it changes the shape of the Halo timeline in a single day. Until this point, the war is defined mainly by colonial defence, fleet battles, and Covenant advance. After this point, the conflict expands into something older and more dangerous. The ring contains secrets that reach back to the Forerunners, and the surviving crew of the Autumn becomes the first human force to confront them directly. In practical terms, 19 September 2552 is the date when Halo itself enters the war. It is also the beginning of a chain of events that leads to the release of the Flood, the destruction of the installation, and a new understanding of what is really at stake in the galaxy.
Key details
Date: 19 September 2552
Location: Installation 04, Soell system
Source: Halo: Combat Evolved (2001)
Significance: Humanity’s first direct encounter with a Halo ring begins here and reshapes the wider war immediately.
Related events
FAQ
Q: When does the Pillar of Autumn arrive at Installation 04 in Halo?
The Pillar of Autumn arrives on 19 September 2552. That is the opening date of the installation campaign shown in Halo: Combat Evolved.
Q: Is Installation 04 the first Halo ring humans find?
Yes. This is the first direct human encounter with a Halo ring in the main Halo timeline. It marks a major shift from a conventional interstellar war into a conflict shaped by ancient Forerunner technology.