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Terran Empire
Terran Empire Logo.png
Seal of the Terran Empire, c. 2155
Dominant species: Terran
Location: Alpha and Beta Quadrants
Capital: Okinawa, Earth
San Francisco, Earth (2250s)
Principal City: San Francisco, Earth
Sovereignty: Earth's Pre-Warp Era to 2293
Military: Imperial Starfleet
System of government: Absolute Monarchy
Legislature: Imperial Senate
Seat of government: Imperial Palace
Head of state: Emperor Spock
Head of government: Emperor Spock
Population: Trillions
Currency: Imperial credit
Language: English
Holiday: Imperial Day
Flag of the Terran Empire.JPG
"Terran strength is born out of pure necessity. Because they live in constant fear, always looking for the next knife aimed at their back. Their strength is painted rust. It's a facade."
Michael Burnham, 2256

In the mirror universe, the Terran Empire is a militaristic Human-dominated governmental authority controlling Earth and surrounding space through the use of the powerful Imperial Starfleet. It was one of the dominant powers in the Alpha Quadrant during the 22nd and most of the 23rd centuries, until being overthrown and conquered by the Klingon-Cardassian Alliance in 2295. In several alternate timelines, the Terran Empire continued to exist as a dominant power well into the 24th century. In at least one of these, it had conquered the Klingon Empire by the 2360s.


References from numerous sources establish that the various depictions of the mirror universe may not take place in concurrent timelines, meaning there could be a number of divergent alternate reality versions of this topic that do not share the same continuity. The references below this note are separated into subsections to minimize confusion regarding the divergences.


There are at least three accounts of the origin of the Terran Empire, the mostly recent, in production terms, also being the canon account.

Neil Armstrong plants the Terran Imperial flag on Luna in 1969.

The Terran Empire had existed for centuries as of 2155, and in 1969, the Empire landed the Predator Eagleon Luna and Neil Armstrong planted the Terran Imperial flag on Luna.

On April 5, 2063, Terran Doctor Zefram Cochrane conducted his first warp flight with his starship the Phoenix, attracting the attention of the Vulcans.

In the mirror universe, first contact was slightly different

Upon landing on Earth and making first contact, Cochrane shot the first Vulcan to exit the ship, allowing his fellow Terrans to board the alien ship and steal the Vulcans' technology; providing the Humans rapid technological advancement leading the early expansion of the Empire. (ENT episode: "In a Mirror, Darkly")

22nd century[]

As of the 22nd century, the Empire had existed for hundreds of years, and had begun its expansion into outer space in 2063, when a Vulcan starship detected the warp drive signature of Zefram Cochrane's warp ship. When the Vulcans landed, their leader was shot by Cochrane, the ship ransacked for its technology and its remaining crew tortured for technological information. By 2155, the Empire, armed with its newly acquired Vulcan technology, went on to conquer not only the Vulcans themselves, but the Andorians, Tellarites, Denobulans and Orions as well. The Empire also committed attacks on the Xindi and Klingons during its aggressive initial expansion.

This rapid expansion eventually proved to be detrimental to the young empire. With its martial resources spreading ever thinner, the Empire was in increasing danger of collapse due to a growing rebellion of its subjugated races. Contrary to Imperial propaganda at the time, the Empire had suffered a series of critical losses, including a major defeat at Tau Ceti, where the Imperial Starfleet lost twelve ships.

In 2155, the Empire's fortunes changed with the appearance of the counterpart universe's USS Defiant into their own universe. Commander Jonathan Archer, aboard the Terran flagship ISS Enterprise (NX-01), mutinied against Captain Maximilian Forrest and took the ship to the Vintaak system where the Defiant was being held by Tholians. Though Enterprise was destroyed in the process, Archer's team managed to wrest the vessel from the Tholians; who had lured Defiant from not only another universe but also over a century into the past. Archer and the survivors of the Enterprise regrouped with the assault fleet but found only the ISS Avenger remaining, under heavy attack from a rebel fleet. Using the advanced Defiant weaponry, Archer defeated the rebels, and afterwards had the Avenger commander, Admiral Gregory Black, vaporized. Archer planned to use his two ships to become emperor himself. The aliens on board Avenger took control of the ship and attempted to destroy the Defiant, though they were unsuccessful and Avenger was destroyed. Archer was later murdered by Hoshi Sato who took the Defiant for herself and used it to destroy Starfleet Headquarters and take the Imperial throne. (ENT episode: "In a Mirror, Darkly")

Hoshi Sato declaring herself Empress

Archer was later murdered by Hoshi Sato who took the Defiant for herself and used it to destroy Starfleet Headquarters and take the Imperial throne. Sato consolidated her power by marrying Thy'lek Shran of the Andorian Imperial Guard. She allowed her new husband to appoint Andorians to high-ranking positions in the Admiralty, intending to ensure the obedience of the remnants of Andoria's military forces. Sato had also intended to order the creation of a binary clone from General Shran's DNA and her own, hoping that a Terran-Andorian hybrid Emperor would further strengthen the ties of the two worlds.

However, Shran went on to betray Sato by luring the Defiantaway from Earth, leaving it to be attacked by the Rebels and sending Sato into exile. As non-Terrans were forbidden to rise to the throne of Emperor, Shran appointed himself "Lord Protector of the Realm", de facto leader of the Empire; until he and now-exiled Empress' "heir" was of age to rule. Shran then planned to use the Empire's military might to destroy Andoria's rivals and promote his home world to rulers of the empire.

On route to her exile on Deneva Sato was captured by the Rebels who put her on trial for the crimes of the Empire. An impassioned speech to T'Pol by Sato convinced her to abandon the Rebellion and help her escape, in return the Vulcans would become equal partners with Terrans in the Empire. This, and the timely arrival of an Imperial assault fleet lead by the Defiant allowed Sato to regain her position and have Shran executed. Sato became the first of a dynasty which ruled until it was overthrown by Spock in 2277. (ENT novel: Age of the Empress)

23rd century[]

Terran Empire seal in 2256

In 2256, the Empire under Emperor Philippa Georgiou continue to fight the rebellion under the Klingon Voq. During this time, Georgiou's adviser, Captain Gabriel Lorca of the ISS Buran and her own adopted daughter Captain Michael Burnham of the ISS Shenzhou both planned a coup to overthrow her. However, Burnham and Lorca were both hunted and believed to have been killed. In truth, Lorca somehow switched place with his counterpart in the prime universe. (DSC episodes: "Despite Yourself", "The Wolf Inside", "Vaulting Ambition", "What's Past Is Prologue", "The War Without, The War Within")

At this time, the Empire's flagship, the ISS Charon, used a Super-mycelial reactor to power itself and it's. Unfortunately, the reactor pulled in power from the Mycelial network and it's usage threatened to destroy the entire multiverse. Following the Empire's attack on the Rebels at Harlak, the Charon was then destroyed by the USS Discovery and Georgiou was taken to the prime universe. Many in the Empire believed she was dead. (DSC episodes: "What's Past Is Prologue", "The War Without, The War Within", "Vaulting Ambition")

By 2267, the Empire was the dominant force in the Alpha-Beta quadrant border region. A freak transporter accident transported an away team from the primary universe over to the ISS Enterprise (NCC-1701) while there the James T. Kirk from that universe suggested to mirror-Spock that the Empire could not continue, and that the only logical solution was peace. (TOS episode: "Mirror, Mirror")

The aftermath of this encounter has several known outcomes; in some timelines Spock follows Kirk’s advice and eventually leads the Empire to be defeated by the Klingon-Cardassian Alliance. In alternate timelines Spock is unsuccessful in bringing about the fall of the Empire, or in other timelines even decides not to follow Kirk's advice and continues to follow the Empire's doctrines.

Fall of the Empire[]

Spock's plan[]

Following Kirk's advice, and a mind meld with Leonard McCoy from the primary universe, Spock resolved to end the Empire. In 2268, in an unprecedented move Coridan joined the Empire through diplomatic (as opposed to military) methods due to the influence of now Captain Spock, who had taken command of the Enterprise through the assassination of Kirk. Spock even went as far to share his vision with his father Ambassador Sarek of Vulcan.

Spock rose to Grand Admiral of Starfleet and later Emperor where he gave the peoples of the Empire greater freedoms, creating a common forum and Senate, disassembling Operation Vanguard as a threat to Galactic peace and ending Project Genesis before it entered its third phase in fear of provoking the Klingons into an arms race. By early 2293, following the destruction of Praxis, the Terran Empire called for diplomatic talks at Khitomer; the Klingons, Romulans, and Cardassians attended with the Tholians refusing the invitation due to lingering tensions over the Taurus Reach. At the talks, all major parties rejected overtures of peace made by the Empire while the Terrans rejected offers of military alliances from the Romulans and Klingons. This action infuriated the Klingon Regent Gorkon who swore to destroy the Terran Empire.

The same year Spock instituted reforms ending the Empire and transforming it into the Terran Republic, preaching disarmament and renouncing preemptive war as foreign policy. This was seen as a sign of weakness by the Empire's neighbors, and in 2295, the Klingons and Cardassians formed an alliance and, with the aid of a fleet of B'rel-class Birds of Prey (which could fire while cloaked), conquered the Republic: ending Terran rule and what remained of the Empire. (TOS - Mirror Universe novel: The Sorrows of Empire)

24th century[]

For the next several decades, humans and associated races were enslaved by the Alliance. Inspired by the visit of Major Kira and Dr. Julian Bashir from the primary universe to Terok Nor in 2370, a Terran Rebellion arose first under the leadership of Benjamin Sisko and, after Sisko's death in 2371, under that of Miles "Smiley" O'Brien. (DS9 episode: "Crossover")

After the final victory of the Terran Rebellion over the Alliance, Earth was once again a free world. Inspired by the example of Spock, humanity chose to follow a new path, and elected not to restore the Terran Empire; rather, Earth became a member of the newly formed Galactic Commonwealth. (TNG - Mirror Universe novel: Rise Like Lions)

Alternate timelines[]


In an alternate timeline, the Terran Empire came about from a Terran-Vulcan alliance that became increasingly militant after discovering the role the Borg played in their first contact. (TOS novel: Spectre)

In another alternate timeline, the Terran Empire was the result of the defeat and subsequent occupation of Earth in the Earth-Romulan War in the 2150s. After ten years under Romulan rule, the Terrans rose up and regained their freedom, vowing to conquer and never be slaves again. (TOS - New Frontiers comic: "Masquerade!")

23rd century[]

Spock's defeat[]

In another timeline by the late 23rd century, "Tiberius the First" ascended to the throne of the Empire however, was betrayed by Spock. Emperor Kirk's Prime Minister disarmed the Empire and preached peace. In response, Kirk brought the Klingons and Cardassians together into an alliance and helped them conquer the Terran Empire. (TOS novel: Spectre)

The Empire Lives[]

Invasion of the prime reality[]

In one timeline, Spock decided against following the advice of the Kirk from the primary universe and instead remained first officer of the ISS Enterprise. In 2285, the Empire launched an invasion of the United Federation of Planets by sending the crew of the ISS Enterprise to replace their primary universe counterparts. (TOS - New Frontiers comic: "... Promises to Keep")

Excelsior crossover[]

Late in the 23rd century the USS Excelsior was on a mission to save the USS Enterprise-A, under Commander Pavel Chekov, and the USS Ranger trapped within the Janus Prime Vortex. While en route, the Excelsior fractured all of its dilithium crystals and loses power; drifting into the vortex. The Excelsior was then transported to a version of the mirror universe where it encountered the ISS Enterprise-A and the ISS Ranger. Commander Chekov destroyed the ISS Ranger and then attacked the ISS Excelsior. After the conclusion of the battle, the Janus Prime vortex is destroyed; as is the Excelsior's way home. Their only choice was to traverse the hostile alternate universe trough the Imperial Terran Empire where they encounter rogue Klingons, a starbase and the ISS Renegade, the M-5 computer, and finally an abandoned starbase along the Klingon border. While in the Klingon Empire, they encountered little resistance until they reach the Klingon homeworlds. There, they found the planet killer being escorted by a fleet of Terran starships. After saving the Klingon homeworlds, the Excelsior gained the trust of the Klingons. They then battled the First Federation starship Fesarius before travelling to the Romulan Star Empire. Inside the Romulan Neutral Zone, they found the hulks of several Terran warships. They then encountered the giant space amoeba and destroy it again; gaining the gratitude of the Romulans. Finally, through the Tholian Empire they then reached the Janus Ultima Vortex, having one final battle with the Terrans and ISS Excelsior before returning to the primary universe. (TOS video game: Shattered Universe)

Dark Mirror[]

24th century Terran Starfleet badge emblem

In an alternate timeline, the Terran Empire is commonly known as the United Empire of Planets. In this timeline, Spock was assassinated in 2279 before his reforms could be implemented. As a result, the Empire continued to exist into the 24th century and controlled all known space after conquering the Klingons and defeating the Romulans centuries before. (TNG novel: Dark Mirror)

Fearful Symmetry[]

In a permutation of the mirror universe in which the Terran Empire survived well into the 24th century, Bajor was still a subject world of the Empire in 2377. The planet's military governor was the Imperial Starfleet officer Fleet Captain Benjamin Sisko, a man distinguished by a scar across his right eye, given to him by his treacherous father. He eventually discovered the Bajoran wormhole and became the Emissary of the Prophets. (DS9 novel: Fearful Symmetry)


In one possible permutation of the mirror universe which was encountered through a quantum fissure in 2380, the Terran Empire still existed. (TNG novel: Q & A)

25th century[]

By 2409, in at least one timeline, the rebellion had succeeded and a restored Terran Empire was once again a major power in the quadrant. (STO mission: "Crack in the Mirror")

Rulers of the Terran Empire[]

Controlled planets:

Subjugated species[]

Subjugated species[]

  • Vulcans (subjugated some time between 2063 and 2074)
  • Kzinti (conquered and made extinct in 2070)
  • Alpha Centaurans (conquered and enslaved en masse in 2074)
  • Tellarites (conquered some time after 2074)
  • Tiburonese (conquered in 2130)
  • Andorian (conquered some time between 2137 and 2155)
  • Denobulans (subjugated some time before 2155)
  • Gorlans (homeworld destroyed in 2263, but likely subjugated some time prior to 2155)
  • Orions (subjugated some time before 2155)
  • Betans (conquered in 2155)
  • Klingons (homeworld occupied in 2218)
  • Betazoids (conquered in 2230)
  • Bolians (conquered in 2246)
  • Ferengi (conquered in 2250)
  • Kaylar (conquered and enslaved in 2254)
  • Bajorans (conquered in 2255)
  • Mintakans (annihilated by a group including Philippa Georgiou and Sylvia Tilly)
  • Organians (subjugated in the mid 2260s)
  • Talosians (annihilated by the Empire in 2264)
  • Halkans (annihilated by the Empire in 2267)
  • Elaysians (annihilated by the Empire in the 2270s)
  • Rigelians
  • Iotians
  • Deltans
  • Caitians
  • Acamarians
  • Husnock


  • The term "Terran Empire" was first used in the Star Trek: Enterprise episode "In a Mirror, Darkly, Part I", a prequel to TOS's "Mirror, Mirror". Mirror Universe (MU) Humans were referred to "Terrans" on DS9, and a reference was made to "their Empire" in DS9 episode: "Crossover", but the actual phrase "Terran Empire" was first used by Hoshi Sato on "In a Mirror, Darkly, Part I".
  • In the Kelvin timeline mirror universe, the official motto of the Terran Empire appeared on a logo behind Spock. The motto was Terra Regnum Imperium (Imperial Reign of Earth). (TOS comic: "Mirrored, Part 1")


States in the mirror universe
treaty of alliance and mutual defense Galactic CommonwealthRomulan Star Empire
Taurus Pact Breen ConfederacyGorn HegemonyTholian AssemblyTzenkethi Coalition
non-aligned states Borg CollectiveCardassian UnionDominionFerengi AllianceGrigariKazon-OglaKinshayaKlingon EmpireTalarian RepublicThallonian Empire
defunct states Klingon-Cardassian AllianceTerran EmpireTerran RepublicTerran RebellionTerran Protectorate