In the mirror universe, the Terran Empire was the repressive interstellar government dominated by the Terrans from Earth and the mirror universe counterpart of the United Federation of Planets. The Empire ruled by terror, with its Imperial Starfleet acting as its iron fist. Following a long history of violence, at some point, an astronaut planted the flag of the Terran Empire on Earth's moon, Luna. The Terran Empire's initial growth beyond the Sol system was due in large part to Vulcan technology that the Terrans took from them after Zefram Cochrane's first contact and presumably from other defeated races; thus, the Starfleet of the Mirror Universe was somewhat more advanced than its regular counterpart. (ENT: "In a Mirror, Darkly")
The Empire's hold on its territories was initially weak. In the 2150s some of the worlds the Terrans had conquered were rising up against them, leading to a long-running war that was going badly for the Empire. Propaganda however conveyed the message that things were going in the Empire's favor and that the war would be over soon.
By 2155, the Terran Empire had already conquered the Vulcans, Denobulans, Andorians, Orions, and Tellarites and launched attacks against the Klingons and Xindi. However, the flagship of the Empire, the Enterprise, under the command of Captain Maximilian Forrest, had a much more racially diverse crew than its regular universe counterpart, with numerous Vulcans and Tellarites serving as crewmembers.
In that year, a Federation ship from a parallel universe was reported in Tholian space. Commander Archer of the Enterprise mutinied against Captain Forrest to take control of Enterprise and retrieve the ship so its technology could be utilized against the rebellion. The vessel was the USS Defiant, launched in the 23rd century. Enterprise arrived and dispatched a boarding party to gain all information they could about the ship, and destroy it to prevent the Tholians from being able to use it. Unfortunately, during the retrieval operation the Tholians attacked Enterprise and destroyed it, stranding the boarding party aboard the Defiant. (ENT: "In a Mirror, Darkly")
Following the destruction of the ISS Enterprise and the death of Captain Forest, Commander Archer and his away team commandeered the USS Defiant. They proceeded to destroy the Tholian hanger in which the ship was being held and rescued a number of former Enterprise crewmembers, including Hoshi Sato, after apparent consideration of leaving their comrades stranded. Archer made a rendezvous with the ISS Avenger, the flagship of Admiral Black. Archer vaporized the admiral and took command of both vessels. Commander T'Pol and Lieutenant Soval led a mutiny of the non-human crewmembers onboard the Avenger and attacked the Defiant in hopes of destroying it. They were destroyed after Commander Charles Tucker reinitialized the power systems that Phlox had attempted to disable. Commander Archer, acting as Captain, then set a direct course for Earth where he intended to declare himself Emperor of the Terran Empire. However, Hoshi Sato poisoned him with the assistance of his bodyguard Travis Mayweather. The two then took control of the Defiant, and upon arriving at Earth, Sato declared herself Empress. (ENT: "In a Mirror, Darkly, Part II")
In 2267, crewmembers of the USS Enterprise, including Captain James T. Kirk, were accidentaly transported to the Mirror Universe, aboard the mirror-version of the Enterprise, the ISS Enterprise. Before Kirk left, believing that the mirror Spock would one day become captain of the ISS Enterprise, he planted a seed of doubt about the inevitability of the Empire, asking Spock if violence was the only logical answer. Spock promised to consider Kirk's words. (TOS: "Mirror, Mirror")
As Kirk predicted, the mirror-Spock later became the captain of the ISS Enterprise and eventually rose to become Commander-in-Chief of the Empire. He began instituting major reforms, turning the Empire into a more peaceful and less aggressive power. Unfortunately, Spock's reforms left the Empire unprepared to fight against the united Klingon-Cardassian Alliance, which managed to conquer the entire Terran Empire, turning the Terrans themselves into a slave race. (DS9: "Crossover")
See also:
- Mirror universe people
- Mirror universe history
- Terran Empire ranks
- Terran Rebellion