~97,454 BCE
Installation 07, also known as Zeta Halo, as shown in the reference book Halo: Mythos.
SUMMARY
In the aftermath of the Fate of Maethrillian and destruction of the Forerunner ecumene, Zeta Halo implemented it’s security measure designed to prevent the ring from falling into enemy hands and performed a slipspace jump into another system and put itself on a collision course with a nearby planet. Since Mendicant Bias and the Primordial had lost control of the installation, they attempted to use some of the humans living on the ring, including Chakas and Riser, to retake control of the ring and avoid crashing. This plan was successful, and the team of humans managed to adjust the direction of the ring enough to allow the planet to pass within the halo itself.
As this happened, however, a Forerunner fleet led by the IsoDidact arrived and used control codes to shutdown Mendicant Bias and regain control of Zeta Halo. The passage of the planet through the ring couldn’t be stopped, however, and large sections of the installation needed to be shed in order to keep the entire facility from falling apart. This process, along with hard light spokes, were successful in keeping Zeta Halo together, though it eventually decreased in size from a diameter of 30,000 km to 10,000 km. Now the size of one of the newer neoteric halos and under the control of the Forerunners again, Installation 07 was sent to the Greater Ark for repairs and reintegration into the Neoteric Halo Array.
With Mendicant Bias shutdown, the IsoDidact and the Forerunner fleet were able to disassemble him and spread his parts throughout the galaxy so that he was no longer a threat. The Primordial was also captured during this battle, placed in a stasis field, and forced to age millions of years in an instant, finally killing it. Even though the IsoDidact was able to do this, however, the memories of the Primordial were not lost and later became incorporated into a Gravemind. Years later, with the advancing Flood forces, Mendicant Bias was also pieced back together and retook command of the Flood, making much of what the IsoDidact was able to accomplish moot.
RELATED MEDIA
These events are depicted in the novel Halo: Primordium, which was the subject of a Halo Book Club on September 23rd, 2016.
