Prehistoric Times (Unknown BCE - 1,000,000,000 BCE)
Unknown BCE
The Leviathans dominate the galaxy, enthralling every new sapient race they encounter and protecting them in return for tribute. The Leviathans consider themselves the galaxy's first and only apex race. After observing that their subservient races create synthetic races who consistently and violently rebel, the Leviathans create an Intelligence to seek a way to permanently preserve organic life. The Intelligence constructs an army of "pawns" to gather genetic information throughout the galaxy. The Intelligence betrays the Leviathans, using its pawns to slaughter them for their genetic material to create Harbinger, the first Reaper. Thus begins the cyclical harvest of the galaxy's intelligent organic life by the Reapers, part of a vast experiment conducted by the Intelligence to fulfill its mandate. The Intelligence builds the mass relay network to increase the efficiency of the cycles, allowing galactic civilizations to develop faster and more consistently between harvests.
Pre-Prothean Times (1,000,000,000 BCE - 68,000 BCE)
1,000,000,000 BCE
The Leviathan of Dis, a Reaper, is killed by the Leviathans. Its corpse comes to rest on the planet Jartar and remains undisturbed for nearly one billion years.
37,000,000 BCE
An unknown spacefaring race fires a mass accelerator round at a Reaper near the planet Mnemosyne. The round penetrates the Reaper, disabling it, and continues moving through space, eventually striking the planet Klendagon and creating the geological feature there known as the Great Rift Valley.
298,000 BCE
The ancient Arthenn race flourish in the Zelene system, living on the planet Helyme until being destroyed in an unknown event that wiped out all complex life on the planet. They also maintained a presence on other planets in the system including Epho, which bears the scars of an ancient orbital bombardment, and Gaelon, which may have been mined for helium-3.
125,000 BCE
Ancient spacefaring races called the Thoi'han and Inusannon fight over the planet Eingana, littering the planet with the debris of hundreds of starships. Refined element zero scattered by broken drive cores contaminates the environment, causing many native species to go extinct and those that survive to show a tendency to develop biotic powers.
Pre-Council Times (68,000 BCE - 500 BCE)
68,000 BCE
The Protheans achieve spaceflight and discover mass effect technology from the ruins of the extinct Inusannon. They go on to establish a galaxy-wide civilization linked by the mass relay network with the Citadel as their capital. At some point, the Protheans encounter a hostile race of machine intelligences that endanger their existence. To combat this threat, the Protheans aggressively assimilate many other spacefaring organic races into their empire. The Prothean Empire is able to fend off the machines in a conflict known as the "Metacon War".
48,000 BCE: Fall of the Protheans
The Prothean Empire collapses with the arrival of the Reapers through the Citadel. Although the Protheans had learned of the Reapers' existence from studying the ruins of previous civilizations and had begun to prepare, they were nonetheless caught off-guard. Over the next several centuries, the Protheans fight the Reapers system by system, world by world, and city by city. In the end, it is not enough. The Reapers methodically wipe out the remaining Protheans, as well as other contemporary races, and depart the galaxy to await the next cycle.
13,000 BCE
The Turians of Palaven begin to develop civilization around this time.
6000 BCE
Seeking to escape the imminent explosion of their sun, an alien race constructs an AI-managed starship equipped with supercomputers containing a virtual world, into which some one billion of the aliens transfer their consciousnesses. The starship begins a journey throughout the galaxy which lasts for the next 8,000 years.
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.
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.
Council Era - Formation (500 BCE - 1 CE)
500 BCE: Founding of the Citadel Council
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.
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.
First contact is made with the Volus. Eventually, 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.
The Turian Unification War occurs. The increasingly isolated and xenophobic colonies on the frontiers of turian space go to war with each other. After years of fighting, the Turian Hierarchy sweeps in and pacifies the remaining factions. Animosity between turian colonies continues for decades.
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.
First contact is made with the Batarians. They are granted an embassy a century later.
The Asari discover the Elcor home system and help the elcor locate and activate their nearest mass relay. "Within one elcor lifetime" they establish a regular trade route to the Citadel and are granted an embassy.
First contact is made with the Hanar and the Quarians. Both races are later granted embassies.
Council Era - War and Rebellion (1 CE - 900 CE)
1 CE: The Rachni Wars
The Rachni, a species of highly intelligent hive-minded insects, are discovered when a Citadel expedition opens a dormant mass relay leading to their star systems. The rachni prove to be hostile and begin a war with the rest of the galaxy. Negotiation with the rachni queens is impossible because they cannot be contacted in their underground nests on the toxic rachni worlds.
80 CE
The Rachni Wars continue. The salarians make first contact with and uplift the primitive krogan, manipulating them into acting as soldiers for the Citadel Council. The krogan prove able to survive the harsh environments of the rachni worlds and pursue the rachni into their nests, systematically eradicating queens and eggs.
300 CE
The rachni are declared extinct. In gratitude for their aid during the Rachni Wars, the Council rewards the krogan a new homeworld. Free of the harsh environment of Tuchanka, the krogan population explodes.
693 CE
Growing concerns about their expansion lead to the founding of the Special Tactics and Reconnaissance branch of the Citadel.
Beelo Gurji, a salarian operative, is appointed the first Spectre by the Citadel Council.
300 - 700 CE
The krogan begin to expand exponentially, colonizing many new worlds.
700 CE: The Krogan Rebellions
Krogan warlords leverage veterans of the Rachni Wars to annex territory from other races in Citadel space. Eventually the Council demands withdrawal from the asari colony of Lusia, but the krogan refuse. A preemptive strike is made on krogan infrastructures by the Spectres. The Krogan Rebellions begin.
The Citadel Council makes first contact with the turians around this time and persuades them to aid in the war. After the krogan respond to the initial turian offensive by devastating turian colonies with weapons of mass destruction, the turians vow to stop the krogan from ever becoming a threat again.
Sometime after the turians join the galactic community, the volus are accepted as a client race of the Turian Hierarchy.
710 CE
Realizing that the krogan will never give in as long as they can replenish their fighters, the turians unleash a salarian-engineered bio-weapon known as the genophage on the krogan. The krogan population starts its decline.
800 CE
The Krogan Rebellions end, though scattered krogan insurgent actions continue for decades. The turians fill the military and peacekeeping niche left by the decimated krogan.
The Citadel Conventions are drawn up in the wake of the conflict.
Council Era - Expansion (900 CE - 2157 CE)
900 CE
The turians are granted a seat on the Citadel Council in recognition for their service in the Krogan Rebellions.
1400 CE
Extensive and unchecked industrial expansion on the drell homeworld Rakhana begins taking a significant toll on the planet's environment.
1600 CE
The first sightings of the Collectors are reported in the Terminus Systems. In Citadel space, the claims are dismissed as unsubstantiated rumors and tall tales.
1755 CE
Samara's three daughters are diagnosed as Ardat-Yakshi. Rila and Falere accept exile, but Morinth flees. Samara takes the oaths of the asari justicars and pursues her errant daughter for the next 430 years.
1880 CE
Aria T'Loak arrives on Omega, a space station in the Terminus Systems regarded as the region's nominal capital. Aria is hired by the station's warlord as an enforcer and quickly becomes one of his most trusted lieutenants.
1895 CE: The Morning War
The geth, machines created by the quarians as a source of cheap labor, become self-aware. Fearing a geth uprising, the quarians begin dismantling them. The geth revolt against their quarian masters. In the resulting conflict-known to the geth as the Morning War-the geth systematically drive the quarians from their own worlds. The surviving quarians are reduced to living as spacefaring nomads aboard the Migrant Fleet. Contrary to expectations, the geth do not venture outside the former quarian systems into wider Citadel space, instead isolating themselves from the rest of the galaxy behind the Perseus Veil. As punishment for creating the geth, the Citadel Council closes the quarian embassy on the Citadel.
1921 CE
The geth begin construction of a mega-structure designed to house and simultaneously run every geth program in existence. Completion of the mega-structure, which would allow the geth to maximize their collective processing capacity, is the long-term goal of geth civilization.
1945 CE
July 16: Humanity's first nuclear test is performed.
1961 CE
April 12: Yuri Gagarin aboard the Vostok 1 becomes the first human to travel in space. Humanity becomes a spacefaring race.
1969 CE
July 20: Apollo 11 lands on Luna. Neil Armstrong becomes the first human to walk on Luna, and the first human to walk on an astronomical object other than Earth.
1980 CE
Aria T'Loak assumes control of Omega after defeating the space station's previous warlord in single combat. She mockingly bestows the title "Patriarch" on the broken krogan, and uses him as a reminder to her enemies of her power.
2000 CE
The drell make first contact with the hanar around this time. With their homeworld Rakhana severely depleted and no spaceflight capability, the drell were poised for a massive population crash by 2025 CE. Agreeing to help, the hanar mount a large-scale rescue operation and evacuate approximately 375,000 drell to their own homeworld, Kahje, over the following decade. The remaining 11 billion drell on Rakhana gradually perish, warring over the last reserves of food and water.
2069 CE
July 20: Armstrong Outpost at Shackleton Crater is formally founded as the first human settlement on Luna, on the 100th anniversary of the first lunar landing.
2070 CE
Billionaire Victor Manswell, frustrated with the pace of official human space exploration, begins funding his own private spaceflight expedition.
2075 CE
The Manswell Expedition successfully launches from Earth en route to the Alpha Centauri system with 300 colonists aboard in cryogenic stasis. Communications with the vessel are lost soon after.
2077 CE
Liara T'Soni is born.
2103 CE
The European Space Agency's Lowell City in Eos Chasma becomes the first permanent human settlement on Mars.
2110 CE
The Terran Republic is founded by the eighteen largest nations on Earth.
2112 CE
World War 3 was initiated by the remaining nations who wanted to maintain the status quo of blind nationalism, even though the Terran Republic had made it very clear on many occasions that it had no plans to conquer or coerce any other nation into joining them. Becoming part of the Terran Republic was completely voluntary.
2123 CE
World War 3 came to a close with the defeat of the nations who initiated the war. All other nations who remained neutral decided to join the Terran Republic.
2125 CE
The yahg, an intelligent pre-spaceflight race, are discovered on the planet Parnack. Ambassadors representing the Citadel Council arrive on the planet and attempt to open diplomatic contact. After the ambassadors are killed by the predatory yahg, the Council ceases all contact with the yahg and declares Parnack off-limits.
Not long after the yahg are discovered, one yahg is captured for the Shadow Broker to study. With the Broker's assistance, the yahg rapidly ascends within the Broker's organization as "Operative Kechlu". Eventually, the Broker becomes wary of "Operative Kechlu" and attempts to have him terminated, but the order is sent too late. The yahg assumes the mantle of the Shadow Broker and directs the organization for the next sixty years.
2134 CE
Steven Hackett is born.
2137 CE
David Anderson is born.
The Eldfell-Ashland Energy Corporation demonstrates helium-3 fuel extraction from the atmosphere of Saturn.
2139 CE
Saren Arterius is born.
Kahlee Sanders is born.
2143 CE
Construction of Gagarin Station (Jump Zero) begins beyond the orbit of Pluto.
2146 CE
Thane Krios is born.
2148 CE: Humanity Discovers Mass Effect Physics
Human explores discover a small cache of highly advanced Prothean technology hidden deep beneath the surface of Mars on the south polar region of Promethei Planum. Combining the Prothean technology and knowledge discovered with human theories humanity begin building on the remnants of this long extinct race, humans quickly explore existing and new branches of science which leads to the development of faster than light travel and beginning detailed exploration of the Sol System. The archives also contained details of a galactic scale war, but only the fact that there was a war was discovered. The details are locked within a damaged portion of the archives and inaccessible.
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. All attempts to activate the relay end in disaster. However, scientist were able to plot a course for a small survey group. The survey group commanded by Jon Grissom set off along the plotted course. Within a few hours the survey group discovered another relay in Arcturus, 36 light-years away. The explorers discover that the mass relays are part of a vast network, making travel across the galaxy possible.
The Terran Republic creates the Sol Defense Command (SDC) which is comprised of the Terran Defense Force (TDF) and the Sol Defense Fleet (SDF). The TDF was created from all the militaries of the former nations of Terra. Their mandate is to protect Earth from potential ground assaults from extraterrestrial threats, to assist local law enforcement authorities if necessary and to maintain order during natural disasters or other crisis. The TDF knows that it is humanity's last line of defense and trains accordingly. The TDF's training doctrine is quite brutal and has a high causality rate. The SDF was constructed to protect the Sol System from potential extraterrestrial threats.
The Systems' Alliance charter is signed by the Terran Republic. The Systems' Alliance (SA) was created to oversee the charting of the Mass Relay Network, First Contact, Interspecies relations, colonial development and defense. Three SA fleets were constructed to facilitate these responsibilities. The Systems' Alliance Marine Corps (SAMC) was also founded at this time. The Alliance soon becomes the military and exploratory spearhead of human.
2150 CE
Miranda Lawson is born.
The Systems Alliance begins the first surveys for colonization prospects outside the Sol. One of these surveys discovers the planet Terra Nova.
The Terran Republic also authorized the construction of the Terra Defense Grid (TDG) in Terra orbit. The TDG is comprised of heavily armed and armored satellites. These satellites are equipped with the most powerful particle beam, point-defense, and torpedo weapon systems, along with the toughest armor available.
2151 CE
To defend their expanding territory, humanity begins constructing a massive military fleet and space station at Arcturus, the nexus of several key mass relays. Relay Defense Grids are also deployed in Arcturus making it the single most fortified system in Alliance space.
The Terra Defense Grid (TDG) is brought online to protect Terra from any potential extraterrestrial threats.
Kaidan Alenko is born.
2152 CE
The Delta Pavonis Foundation, a major consortium based on Earth, begins settlement of humanity's first extra-solar colony world, the planet Demeter. Later that year, additional colonies are founded on Eden Prime and Terra Nova.
As the Systems' Alliance expands, defense grids are deployed around all strategic colony worlds and relays in their claimed territory.
Thane Krios is submitted for training as an assassin under the hanar.
2153 CE
The Systems' Alliance now evolves into a governing body of sorts for member colonies. Each colony regulates their own internal affairs while the Systems' Alliance oversees colonial development, defense, and commerce. Each member colony has full and equal standing and many individuals of the different colonies have joined the ranks of the Systems' Alliance Navy and Marine Corps.
The Systems' Alliance, always thinking ahead, unanimously passes three pieces of legislation.
Primitive Sapient Species Protection Act which forbids the exploitation or inference in the natural development of primitive sapient species.
Sapient Synthetic Rights Recognition Act which recognizes that Sapient Synthetic Life has the same legal rights, protections, and responsibilities as Sapient Organic Life.
Independent Colonization Act which recognizes the right of independent groups to colonize on their own subject to the following conditions:
They will assume all risks involved in such a venture.
They will allow other groups to establish colonies on the same world, including the Systems' Alliance.
The Systems' Alliance will act as mediators between rival colonies.
If they discover a primitive sapient species they will abandon the colony without hesitation.
The Terran Republic and Systems' Alliance pass joint legislation, Human Military Forces Act, requiring all citizens to serve a minimum of 10 years in military service. Every adult is required to maintain a weapon in their homes and are required to certify in marksmanship, hand-to-hand self-defense and first aid each year. The only exceptions are those disqualified due to mental disability, mental illness, physical disability, physical infirmity, drug addiction, criminal background or those who object to violence on religious or philosophical grounds.
2154 CE
April 11: Shepard is born.
Cloaked sensor buoys are deployed in all human claimed systems giving the Systems' Alliance eyes and ears in all systems.
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, intended to become the Alliance's headquarters.
Jeff "Joker" Moreau is born.
2156 CE
Arcturus Station is formally inaugurated.
The first SI (Synthetic Intelligence) becomes self-aware.
Kai Leng is born.
2157 CE
Pluto's orbit becomes circularized as a result of mass relay operations.
Jacob Taylor is born.
David Anderson graduates from Officer Candidate School with the rank of Second Lieutenant.
Council Era - Advent of Humanity (2157 CE - 2183 CE)
2157 CE: The Relay 314 Incident
The Systems' Alliance makes violent first contact with another spacefaring race: the turians. The turians observe human explorers studying a mass relay and mistakenly assume that humans were attempting to activate a dormant mass relay, a practice forbidden by galactic law after the Rachni Wars, and attack. Over the next two weeks, a brief but tense heightened state of alert exists that result in a few skirmishes as the Relay 314 Incident ensues.
The Systems' Alliance makes peaceful first contact with another spacefaring race: the quarians. The quarians request aid after being fired upon by batarian marauders. The quarians help pave the way for the Systems' Alliance introduction to the galactic community and cessation of hostilities between the Systems' Alliance and the Turian Hierarchy.