A timeline of all major events in the Halo universe from the time of the Forerunners through the rule of the Created.
The Callisto Incident was a series of events involving the UNSC Callisto that is considered the first true insurrectionist attack from January to March 2494.
The Second Battle of Harvest, also known as just simply the Battle of Harvest, was humanities first attempt to recover the planet Harvest from the Covenant, who wiped out the existing colony and killed tens of thousands of civilians a year earlier.
The Harvest Campaign was a five-year campaign to retake the planet Harvest after the Covenant took over the planet and wiped out the colony on Harvest.
The Battle of Alpha Aurigae was a large naval battle between UNSC and Covenant forces in the Origami Asteroid Field of the Alpha Aurigae system, culminating in a UNSC victory.
The Battle of Hat Yai was a battle early in the Human-Covenant War that took place between late 2528 and early 2529.
The Battle of the Great Bear was a naval battle between a UNSC fleet of seventeen warships and three Covenant warships in the Groombridge-1830 system.
In an effort to limit the ability for the Covenant to discover human colonies, including the inner colonies and Earth, the Cole Protocol was established to wipe all ship navigation data when the UNSC came into contact with any Covenant forces.
The Battle of Leonis Minoris was a battle between Covenant and UNSC forces in the Leonis Minoris system sometime in 2537.
The Battle of Kholo was a Covenant assault on the human colony world of Kholo sometime in 2539.
The Battle of Psi Serpentis was a major conflict between a UNSC fleet of 162 warships led by the UNSC Everest and Admiral Preston Cole and two fleets of Covenant warships totaling over 300 ships in the Psi Serpentis system in April 2543.
The Battle of Skopje was a conflict between the Covenant and UNSC forces on the colony world of Skopje, sometime in 2547.
The Algolis Invasion was a Covenant attack on the human colony world of Algolis in the Algol system sometime between 2548 and 2552.
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.
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 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 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.
~97,745 BCE
Around 97,745 BCE, nearly nine-thousand years since the Flood disappeared from the galaxy during the Human-Forerunner Wars and three-hundred years before the Great Purification, the Flood were first observed at the edges of the galaxy on the planet Seaward, a Forerunner colony world.
