Timeline of events in the Mass Effect universe
Timeline
* Events from the second part of the game and all its expansions were not considered while composing this post.
This is the timeline of events in the universe of Mass Effect. All dates are given in B.C. (Before Common Era) and C.E. (Common Era).
Period before the formation of the Council:
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Approx. 48000 B.C.
The Protheans - a highly advanced galactic civilization, whose worlds were connected by a network of mass relays - mysteriously vanished, leaving behind only ruins. Most of the technology used by subsequent races, such as humans, is ultimately based on their artifacts. Archeologists believe they may have been destroyed by some global cataclysm.
Approx. 1900 B.C.
A global conflict on the home planet of the Krogan, Tuchanka, ends with a nuclear winter, turning the planet into a radioactive wasteland. The Krogan split into clans, engaged in an eternal conflict with each other.
Approx. 1800 B.C.
A supernova displaces one of the mass relays and its location is lost.
Approx. 580 B.C.
Having developed faster-than-light engines based on Prothean technology, the Asari begin exploring the mass relay network, becoming the first to discover the massive space station known as the Citadel, built millennia ago in the Serpent Nebula.
Approx. 520 B.C.
The Salarians discover the Citadel shortly after the Asari, and diplomatic relations are established between these races.
Period after the formation of the Council:
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Approx. 500 B.C.
Together, representatives of the two civilizations - the Asari and Salarians - explore the Citadel, ultimately proclaiming it the center of the galactic community under the jurisdiction of the Citadel Council.
The Salarians reveal the existence of their own Unified League. Faced with a blatant threat, the League responds by assassinating all ruling members of the Union, which subsequently destroys the League.
The beginning of the Turian Rebellions.
From this year, standard Galactic (SG) dating begins.
Approx. 500 B.C. - 1 C.E.
The Council races begin to expand the galactic community, establishing relations with other space-faring civilizations and inviting them to the Citadel. This is an era of expansion of the galactic community marked by sporadic conflicts.
First contact is established with the Vorcha; however, they are initially not allowed to establish a permanent embassy on the Citadel. With the involvement of the Vorcha, a unified galactic currency - credits - is established, connecting the economies of numerous planets.
200 B.C. (Exact Date)
The Council permits the Vorcha to open a permanent embassy on the Citadel, though they are not allocated a seat on the Council.
200 B.C. - 1 C.E.
Approximately a century after first contact with the Citadel Space, the Batarians establish their embassy.
The Asari come to the Elcor star system, assisting them in finding and activating the nearest mass relay. The Elcor establish trade and economic relations with the Citadel and soon open their own embassy.
First contact is established with the Hanar and Quarians. The Quarians open an embassy.
1 C.E.
Rachni Wars
An expedition using a recently discovered mass relay reaches star systems populated by the Rachni - a highly advanced insectoid race bound by a collective consciousness. The latter unleash a war of galactic proportions. The Council cannot negotiate, as the Rachni queens are deep underground on extremely toxic Rachni planets.
Approx. 80 C.E.
The Salarians save the Krogan from self-imposed nuclear winter, providing them with advanced technology and relocating them to more hospitable planets to use them as soldiers.
300 C.E.
The Krogan population grows. After just two generations, the Krogan have reproduced to such an extent that they can not only defeat the Rachni but also invade their home world and commit genocide against that race. In gratitude for their assistance in the Rachni Wars, the Council grants the Krogan a new resource-rich planet.
Approx. 300-700 C.E.
The Krogan begin colonizing many new worlds. Concern over their rapid expansion leads to the creation of the Special Tactical Reconnaissance Corps (Spectres).
700 C.E.
Krogan Uprisings
A time period known as the Krogan Uprisings. The Krogan population experiences a demographic explosion. The Krogan use their newfound power to create colonies by force. The Council seeks help from the recently established Turian Hierarchy. The Turians, after not very successful battles, unleash a genophage developed by the Salarians on the Krogan, leading to near-total destruction of newborns. Seeing that their main advantage was lost, the Krogan surrender to the Turians. Due to the genophage, only 1 in 1000 pregnancies was successful. The Turians accept the Vorcha as a secondary race in the Hierarchy.
800 C.E.
The Krogan Uprisings are completely over. The Turians fill vacancies in military and peacekeeping forces created after the Krogan Uprisings.
900 C.E.
The Turians, rewarded with a seat on the Citadel Council for their help in resolving the conflict, and their fleets serve as galactic peacekeepers.
Approx. 1600 C.E.
The Collectors are first discovered in the Terminus Systems at the Omega-4 mass relay. Very little is known about this mysterious race, and most Council races consider stories about the Collectors to be mere galactic legends.
Approx. 1900 C.E.
Geth War
The Quarians create an evolving artificial intelligence known as the Geth. When the Geth evolve to the point of achieving self-awareness, the Quarians, fearing a rebellion, act quickly to try to destroy the Geth. Unfortunately, it is already too late; the Geth fight for their survival and ultimately prevail. The Quarians are forced to leave their planet and lead a nomadic life on their fleet of barely functional ships. Contrary to expectations, the Geth do not leave the confines of Quarian star systems, isolating themselves from the galactic community behind the Perseus Veil. In retaliation, the Council closes the Quarians' embassy on the Citadel.
1900 C.E. - 2100 C.E.
The galactic community continues to expand. Aside from the Geth Wars, this is an era of peace and prosperity.
Modern Era
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2069 C.E.
July 24, the 100th anniversary of the first human landing on the Moon.
Humans establish the Armstrong Complex in the Shackleton Crater, which becomes the first human settlement on the Moon.
2077 C.E.
Matriarch Benezia gives birth to Liara T'Soni with an unknown Asari.
2103 C.E.
The first permanent human settlement by the European Space Agency on Mars is Lowell City in Eos Chasma.
2137 C.E.
David Anderson is born.
The Ashland Energy Corporation demonstrates helium-3 extracted from Saturn's atmosphere.
2139 C.E.
Saren Arterius is born.
Kaeli Sanders is born.
2142 C.E.
Construction of the