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Great Purification

Great Purification

~97,445 BCE

A halo firing, sending it’s pulse across the galaxy during the firing of the Halo Array at the end of the Forerunner-Flood War, c. 97,445 BCE.




The Great Purification was the final event of the Forerunner-Flood War, purging the entire Milky Way galaxy of all sentient life, including Forerunners, the Flood, and any other species that may have survived the Flood infestation. Having exhausted all other options, and with only a handful of Forerunners left after the Battle of the Greater Ark, the IsoDidact activated the Neoteric Halo Array, sending a superluminal pulse through every star system, wiping out the Flood threat, and paving the way for new species to evolve and become the dominant force in the galaxy.

In the aftermath of the Great Purification, the Librarian’s plan to reseed the galaxy with many of the species lost, known as the Conservation Measure, went into effect, sending hundreds if not thousands of ships loaded with plant and animal specimens to repopulate those worlds devastated by the firing of the halos. Over the next several hundred years the galaxy recovered, and at the completion of the Conservation Measure, all remaining Forerunners left the galaxy.




These events are depicted in the novel Halo: Silentium, which was the subject of a Halo Book Club on January 31st, 2018.


Earlier Event: January 1
Return to Maethrillian
Later Event: January 1
Judgement of the Didact