Galactic Timeline
A comprehensive chronicle of major galactic events from the rise of the Leviathans to the Reaper War.
Ancient Era
Unknown regions of the galaxy
Establishment of first known galactic civilization
Unknown
Creation of the first AI overseer
Set in motion events leading to the Reaper cycle
Multiple systems across the galaxy
Creation of the first Reaper and beginning of the cycle
Billions of Leviathans
Near extinction of Leviathan species
Establishment of the cyclical harvest pattern
Pre-Prothean Era
Throughout known space
Advanced civilization that influenced Prothean development
Entire species
Complete extinction of species
Technology and artifacts discovered by Protheans
Multiple star systems
Beginning of Prothean dominance
Establishment of initial Prothean colonies
Foundation of galactic civilization
Various research centers
Major technological advancement
Rapid technological progress
Technologies discovered by modern races
Prothean Era
Entire known galaxy
Establishment of first unified galactic government
Unknown
Galaxy-wide Prothean dominion
Development of mass effect technology foundation
All Prothean systems
Fall of the most advanced known civilization
Trillions of Protheans and subject species
Near-total extinction of Protheans
Loss of vast technological knowledge
Ilos research facility
Creation of secret Mass Relay
Most of the Ilos research team
Successful creation of mini mass relay
Crucial to defeating Sovereign in modern era
Council Formation
Widow System
Foundation of modern galactic government
None
Establishment of Citadel as galactic capital
Creation of unified galactic community
Citadel Space
Formation of Citadel Council partnership
None
Creation of two-species Council
Framework for modern galactic politics
Rachni Wars
Rachni space
First contact with hostile species
Initial exploration team
Beginning of Rachni Wars
Council restrictions on relay activation
Multiple systems across Council space
First major galactic war
Millions of Council species citizens
Decision to uplift the Krogan
Shaped future Council military policy
Modern Era
Mars, Sol System
Human discovery of mass effect technology
None
Rapid human technological advancement
Humanity's emergence as galactic power
Shanxi colony
Humanity's introduction to galactic community
623 humans, 1,200 turians
Peace negotiations and diplomatic relations
Complex human-turian relationship
Eden Prime colony
First modern encounter with Reaper technology
Thousands of colonists
Investigation of Saren and discovery of Sovereign
Beginning of modern Reaper war
Citadel
First major battle against a Reaper
Thousands of military and civilian
Destruction of Sovereign
Proof of Reaper existence
Various human colonies
First confirmation of Collector presence
Increased colony defenses
Led to investigation of Collector threat
Bahak System
Delayed Reaper invasion
300,000+ Batarian colonists
Destruction of Bahak System
Strained Human-Batarian relations
Human colonies in Terminus Systems
Revelation of Collector threat
Hundreds of thousands of colonists
Destruction of Collector base
Delayed Reaper invasion plans
Galaxy-wide
Culmination of Reaper harvest cycle
Billions across all species
Activation of Crucible
End of Reaper threat and transformation of galaxy