Timeline

This is the timeline of the Mass Effect universe. All dates are in BCE (Before Common Era) and CE (Common Era).

48000 BCE (Approximate)
The Protheans, a galaxy-wide civilization linked by the mass relay network, mysteriously vanish, leaving only ruins behind. Much of the technology in use by younger species, such as humans, is eventually based on their artifacts. Archaeologists believe that they were destroyed in a cataclysm.

1900 BCE (Approximate)
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 (Approximate)
A supernova propels one of the mass relays out of its position. The dense nebula formed by the supernova means the relay's position is effectively lost.

580 BCE
After developing faster-than-light spacefaring capabilities based upon Prothean technology, the asari begin to explore the mass relay network, and eventually discover the huge Citadel space station at a hub of many mass relays.

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 station and establish it as a center of the galactic community, led by the Council. The Salarian Union open the records of their own League of One. Under threat, the League responds by assassinating the whole inner cabinet of the Union; the Union then wipes out the League.

The turian Unification War begins.

This year is also known as 0 GS, the beginning of the Galactic Standard (GS) timeline.

500 BCE - 1 CE (Approximate)
The Council races begin expanding the galactic community, opening first contact with other spacefaring races and integrating them into the Citadel. This is a period of rapid growth and occasional conflict.

First contact is made with the volus although at first they are not permitted a permanent embassy on the Citadel. With their participation, a single galactic currency - the credit - is eventually established, linking all galactic economies.

200 BCE (Exact)
The Council agrees to grant the volus the honour of being the first species with an embassy at the Citadel, but not a Council seat.

200 BCE - 1 CE
The batarians post an embassy, a century or more after first contact.

The asari stumble into the elcor system, and help them to locate and activate their nearest mass relay. "Within one elcor lifetime" they establish a regular trade route to the Citadel and soon post an embassy.

First contact is made with the hanar and the quarians. The quarians post an embassy.

The Rachni Wars
The Citadel Council first encounters the rachni, a species of highly intelligent hive-minded insects. They are discovered when an expedition opens a dormant mass relay to their star systems. The rachni prove to be hostile and begin a war with the rest of the galaxy. The Council cannot negotiate because they cannot contact the rachni queens that live underground on the toxic rachni home worlds.

80 CE (Approximate)
The Rachni Wars continue. The salarians transplant the primitive krogan to another world and manipulate them into acting as soldiers for the Citadel Council. The krogan are able to survive the harsh environments of the rachni worlds, and begin a strategy of eradicating queens and eggs.

300 CE
The rachni are declared extinct. In gratitude for their aid during the Rachni Wars, the Council grants the krogan a new homeworld. Free of the harsh environment of Tuchanka, the krogan population explodes.

300-700 CE (Approximate)
The krogan begin to expand exponentially, colonizing many new worlds. Growing concerns about their expansion lead to the founding of the Special Tactics and Reconnaissance branch of the Citadel.

The Krogan Rebellions
Krogan warlords leverage veterans of the Rachni Wars to annex territory from others in Citadel space. Eventually the Council demands withdrawal from the asari colony of Lusia, but the krogans refuse. A pre-emptive strike is made on krogan infrastructures by the Council, using the newly-created Spectres. The Krogan Rebellions begin.

First contact is made with the turians. In response to krogan threats, they declare war. After the krogan devastate turian colonies with weapons of mass destruction, the turians respond with a salarian-engineered bioweapon, known as the genophage. The krogan population starts its decline.

The turians accept the volus as a client race within the Hierarchy.

800 CE
The Krogan Rebellions end. The turians begin to fill the military and peacekeeping niche left by the decimated krogan.

900 CE
The turians are granted a place on the Citadel Council, and their fleet acts as a galactic peacekeeping force.

The Geth War
The quarians create the geth, intended to be a source of cheap labour. The quarians notice geth showing signs of independent thinking, and plan to destroy them before they have chance to become self aware. The geth rebel against their quarian masters and, in the resulting war, reduce the quarians to a species of space faring nomads aboard the Migrant Fleet. Contrary to expectations, the geth do not venture outside the former quarian star systems, instead isolating themselves from the rest of the galaxy behind the Perseus Veil. In punishment for their actions, the Citadel Council closes the quarian embassy on the Citadel.

1900 CE-2100 CE
The galactic community continues to expand. With the exception of the Geth War, this period is a time of peace and prosperity.

2069 CE
Armstrong Outpost at Shackleton Crater becomes the first human settlement on Luna. It is formally founded on July 24, the 100th anniversary of the first lunar landing.

2077 CE
Liara T'Soni is born to Matriarch Benezia and an unknown asari.

2103 CE
The European Space Agency's Lowell City in Eos Chasma becomes the first permanent human settlement on Mars.

2137 CE
David Anderson is born.

Ashland Energy Corporation demonstrates helium-3 fuel extraction from the atmosphere of Saturn.

2139 CE
Saren Arterius is born.

Kahlee Sanders is born.

2142 CE
Construction of Gagarin Station (Jump Zero) begins beyond the orbit of Pluto.

2148 CE
Humanity discovers a small cache of highly advanced Prothean technology hidden deep beneath the surface of Mars on the south polar region of Promethei Planum. Building on the remnants of this long extinct race, humans quickly explore the science of mass effect fields, leading to the development of faster than light travel and beginning detailed exploration of the solar system.

2149 CE
Following information from the translated data cache on Mars, humans discover that Charon, Pluto's moon, is actually a massive piece of dormant Prothean technology - a mass relay - encased in ice.

Once activated, Jon Grissom leads the first team of explorers through the relay. They discover that the Charon Relay allows instantaneous travel across thousands of light-years to a synchronized mass relay in another part of the galaxy.

The Systems Alliance charter is signed by the eighteen largest nations on Earth. The Alliance soon becomes the military and exploratory spearhead of humanity.

2151 CE
To defend its rapidly expanding empire, humanity assembles a massive fleet and begins construction of an enormous military space station at Arcturus, at the nexus of several key mass relays... even though they have yet to encounter another intelligent space-faring species.

An accident at Singapore International Spaceport exposes a human population to dust-form element zero.

Kaidan Alenko is born.

2152 CE
The Systems Alliance begins settlement of Earth's first extra-solar colony world, the planet Demeter.

Roughly 30% of the children born in Singapore after element zero exposure suffer from cancerous growths.

2153 CE
Pallin becomes the Executor of C-Sec.

2154 CE
Commander Shepard is born.

2155 CE
Saren Arterius is promoted to active service in the turian military at the age of 16.

The Systems Alliance occupies completed portions of Arcturus Station as a headquarters.

2156 CE
Charon is revealed to be a Mass Relay encased in ice. Jon Grissom leads an expedition through, setting a precedent for more jumps.

2157 CE
Pluto's orbit becomes circularized as a result of Mass Relay operations.

David Anderson graduates from OCS with the rank of Lieutenant.

The First Contact War
Humanity makes first contact with another space-faring culture: the turians. Unfortunately, the encounter is far from peaceful. The turians find the human fleet attempting to activate a mass relay, something forbidden in galactic law after the Rachni Wars, and attack. Over the next several months, a brief but tense conflict known on Earth as the First Contact War ensues. David Anderson, newly graduated from the Alliance's elite N7 programme, serves with distinction alongside Jill Dah. Saren's brother is one of the turian casualties. Finally General Williams is forced to surrender the garrison at Shanxi to the turians.

Admiral Kastanie Drescher leads the Second Fleet against Shanxi, catching the turians by surprise and evicting them from the planet.

The turians gear for a full war against humanity, but this draws the attention of the Citadel Council. The Council intervenes before hostilities escalate further, revealing the existence of the greater galactic community to humanity and brokering a peace between them and the turians.

2158 CE
Humans learn potential of biotics. An international effort to track element zero exposures begins. Roughly 10% of exposed children show some sign of biotic ability.

April 14: Ashley Williams is born.

2159 CE
Saren becomes the youngest turian to enter the Spectres.

2160 CE
Systems Alliance Parliament formed.

With the existence of human biotics firmly established, the BAaT programme is set up on Gagarin Station to train potential candidates and develop biotic implants.

2161 CE
Amid concerns over gene therapy and genetic modifications being misused, the Alliance Parliament passes the Sudham-Wolcott Genetic Heritage Act.

2162 CE
Construction of Arcturus Station is completed.

A survey team working for a batarian entrepreneur, Edan Had'dah, discovers a mysterious artifact orbiting an unnamed planet near the Perseus Veil.

2163 CE
The Alliance secretly begins illegal AI research at a base on Sidon with Dr. Shu Qian as project leader. Lt. Kahlee Sanders is assigned as a tech analyst.

First experimental 'L1' biotic implants used in humans.

Harkin becomes the first human C-Sec officer.

The Alliance begins charting the Voyager Cluster.

Kumun Shol and his army of mercenaries begin excavating the surface of Klencory.

A survey team reports strange disturbances in the clouds of Logan. Upon investigation however, the signals disappear.

2165 CE
Humanity continues to expand, founding more colonies and establishing trade alliances with many of the other species who recognize the authority of the Citadel Council. In 2165, the Council makes official recognition of humanity's growing power and influence in the galactic community. Humanity is granted an embassy on the Citadel, the political and economic heart of the galaxy. Tensions grow between humans and batarians as they compete for territory in the Skyllian Verge.

The events of Mass Effect: Revelation occur. Saren uses files taken from Dr. Shu Qian and Edan Had'dah to start searching for the artifact discovered near the Perseus Veil.

2166 CE
A turian mercenary, Commander Vyrnnus, is hired to oversee training at BAaT.

2167 CE
L2 biotic implants first developed and used in humans; Kaidan Alenko is among the first to receive the new implants.

2169 CE
Kaidan Alenko accidentally kills Commander Vyrnnus after being provoked. The diplomatic fallout with the turians results in BAaT being shut down.

2170 CE
The human colony of Mindoir is attacked by batarian slavers. Many colonists are killed or captured.

Another human colony, Yandoa, suffers catastrophic dust-form element zero exposure to its atmosphere when an Eldfell-Ashland Energy ship explodes in orbit. Many children suffer birth defects; thirty-seven biotic children are born, including Gillian Grayson.

L3 biotic implants are developed after the L2 implants prove to be dangerous.

2171 CE
In protest at the Council's refusal to check human expansion in the Skyllian Verge, the batarians close their embassy, withdraw into their home systems, and effectively become a rogue state.

2173 CE
A fly-by over the world of Armeni discovers odd surface portrusions. Upon closer inspection, they turn out to be elaborate crypts for the zeioph, a now extinct former space-faring race. Various human universities seek to perform excavation. Council Law forbids this however, and a debate ensures.

Terra Firma is involved in a Nashan Stellar Dynamics kickbacks scandal, forcing Inez Simmons (the current party leader) to resign. Charles Saracino becomes the new party leader after his opponent, Claude Menneau, mysteriously vanishes while en route to Shanxi.

Risa Uvarsen uses the terrain of Faringor to film the external scenes of the movie Starless.

The Leviathan of Dis disappears, coinciding with the arrival of a batarian dreadnought.

Golo is exiled from the Migrant Fleet for trying to sell quarians to the Collectors.

Kaidan Alenko enlists in the Alliance Navy.

2174 CE
Ashley Williams finishes high school and enlists in the Alliance military.

2176 CE
Batarian-funded pirates and criminals launch a surprise attack on the human colony of Elysium, later known as the Skyllian Blitz. The assault is repulsed by the Alliance fleet and ground teams.

2177 CE
During a recon mission to find a missing colonial pioneer team on Akuze, a unit of fifty Alliance marines is wiped out by thresher maws.

2178 CE
The Alliance tracks several pirate FTL exit vectors during the 'Theshaca Raids'. In retaliation for the Skyllian Blitz, the Alliance launches a major offensive against the moon of Torfan and destroys the criminal bases there, mostly populated by batarians. The threat against human colonies from batarian extremists is curtailed.

Tali'Zorah nar Rayya’s mother dies after contracting an airborne virus aboard the Flotilla.

ExoGeni Corporation announces its decision to settle the world of Feros.

2179 CE
A colony on Proteus is founded.

2183 CE
Humans and turians collaborate on an engineering project co-founded by the Citadel Council - an experimental frigate with a prototype stealth system, the SSV Normandy. The Normandy is commissioned with Captain Anderson in command. Commander Shepard - now a promising young officer in the Alliance Navy - is assigned as XO.

The colonization of Chasca begins.

June 17: Ashley sends a response email to her sister.

The events of Mass Effect occur.

The events of Mass Effect: Ascension occur.

L4 biotic implants are developed.

The quarian Migrant Fleet changes its conservative policy, sending ships out to look for new homeworlds.