Ilos Archives
Historical information
Built:	March 30, 64712 BCE
Purpose:	Military weapons and technology development projects
Facility information
Affiliation:	Prothean Empire
Armament:	Numerous automated defenses
Era:	Prothean Cycle Malantorian Era Reaper Era Asari Cycle Pre-Interstellar Era Thessian Era Council Era Imperial Era Pax Galactica Era Human Cycle Reformation Era Dominion Era Post-Cycle Pax Aeterna Era

The Ilos Archives was a prothean imperial military facility located in the heart of Trakkar Capital on Ilos. Following the Prothean Empire's discovery of the planet, the construction of Trakkar Capital followed shortly after as a small research outpost to study the Inusannon technology there: the largest amount of Inusannon technology yet found by the protheans up until that point. However, military interest in the reseach gleaned from the planet would lead to the construction of a classified research installation within the ruins of an Inusannon bunker, utilizing the superstructure of the bunker to mask the existence of the facility itself. Dubbed the "Ilos Archives", the installation not only collated all the prothean research on the Inusannon into a single repository of knowledge, but also allowed the protheans to conduct experiments in secret, as well as commission numerous weapons and other technological projects deemed important to maintaining the Empire's colossal war machine. When the Metacon Wars broke out in 60123 BCE, the Ilos Archives was immediately set to the task of designing new weapons and technology to augment the prothean war effort, and among these would be the Conduit project; the successful development of a prothean-made mass relay prototype. The facility was manned by the Templar-class VI Vigil, and possessed an extensive array of stasis units for the personnel in case of emergency.

When the Reapers invaded in 60101 BCE and captured the Citadel, they were left unaware of the Ilos Archives' existence due to Ilos being removed from prothean star charts to keep it secret from their enemies. The entire planet was put on lockdown, and the Ilos facility went dark as it ignored all attempts to contact it. When the personnel realized the war would likely last centuries, they went into stasis until the Reapers left: by the time they woke up nine thousand years later however, the vast majority of the remaining personnel had died. The remaining scientists used the Conduit to get on the Citadel and sabotage the Reaper signal. The Ilos Archives went dark for the next forty thousand years, at which time nature, which had already reclaimed Trakkar Capital, began to reclaim the facility as well. By the time the Archives were finally rediscovered in 2183 CE by Saren Arterius, much of the facility was running on its last reserve power. After Vigil gave the Normandy Squad the information they needed to defeat Saren and his forces and stop the return of the Reapers, the facility lost what was left of its remaining power, going offline permanently.

During the Dominion Era, Prometheus would use the facility to do research on the Conduit, eventually using research gleaned from it for projects such as Project Requiem, and eventually for the construction of their own mass relays. After the Dominion Civil War, Ilos was declared off limits by the Unified Galactic Republics, so the Archives have not been disturbed since, the last remnant of what remained of the fallen Prothean Empire.