5,000 BCE - 0

### 1900 BCE

* Tuchanka, the krogan homeworld, enters the nuclear age. In a global conflict, weapons of mass destruction are released, triggering a nuclear winter. In the resulting devastation, krogan society devolves into a collection of warring clans.

### 1800 BCE

* A supernova propels the Mu Relay, the only point of access to the remote Pangaea Expanse, out of position. Concealed somewhere in the dense nebula formed by the supernova, the relay's position is effectively lost for centuries. Later, the rachni rediscover the relay.

### 664 BCE

* The batarian hero Harz began his Conquest of the Three Continents.

### 684 BCE

* Harz completes his quest, taking his coalition of four nations and across two seas and conquering twelve of the fifteen major nations of ancient Khar'shan.

### 580 BCE

* After developing faster-than-light spacefaring capabilities based upon Prothean technology, the asari begin to explore the mass relay network.

### 560 BCE

* The asari discover the Citadel, and with the help of the Keepers discover more relays and develop a buoy-based communications method, based upon a stash left behind by the Inusannon.

### 554 BCE

* Having devised up an expansive communications grid to keep up constant chatter between their colonies, the Asari Republics are officially founded, the loose governing system of the species.

### 520 BCE

* The salarians discover the Citadel and open diplomatic relations with the asari.

### 500 BCE

* The Citadel Council is formed. The asari and salarians together colonize the Citadel and establish it as a center of the galactic community, led by the Council. This year is also known as 0 GS, the beginning of the Galactic Standard (GS) timeline.

### 490 BCE

* As a gesture of openness with their new asari allies, the Salarian Union opens the records of the League of One. Under threat, the League responds by assassinating every member of the Union's inner cabinet; Special Tasks Group operatives then hunt down and eliminate the League.

### 463 BCE

* The turian Unification War begins. The increasingly isolated and xenophobic colonies on the frontiers of turian space begin a war amongst themselves.

### 449 BCE

* After years of fighting, the Turian Hierarchy sweeps in and pacifies the remaining factions in the Unification War. Animosity between turian colonies continues for decades.

### 515 BCE

#### January

* **5th -** The batarian War of Peace begins.

### 512 BCE

#### October

* **1st -** The Batarian Hegemony is founded, and almost immediately the species is thrust into an industrial revolution.

### July

* **8th** - Batarian/Volus First Contact occurs

### 266 BCE

##### October

* **19th** -First contact is made with the batarians.
* First contact is made with the volus.

### 230 BCE

* The Citadel Council commissions the volus to draw up the Unified Banking Act, which establishes a standard galactic currency known as the credit and links all galactic economies.

### 229 BCE

* The asari discover the elcor home system and help the elcor locate and activate their nearest mass relay.

### 209 BCE

* First contact is made with the quarians.

### 201 BCE

* The Council grants the volus the honor of being the first non-Council species with an embassy at the Citadel, rather than a Council seat.

### 198 BCE

* The elcor and the quarians are granted embassies on the Citadel.

### 140 BCE

* The hanar are granted an embassy on the Citadel.