|Alliance Forces||Romulan Star Empire|
The Earth-Romulan War, also known as the Romulan War, was a major interstellar conflict fought from 2156 to 2160 between the forces of United Earth and those of the Romulan Star Empire. Earth was assisted by its allies Vulcan, Tellar, and the Andorian Empire. (ENT: "In a Mirror, Darkly, Part II", TOS: "Balance of Terror")
In the early 2150s, Earth began to make impressive diplomatic and military advancements in the Alpha Quadrant. Major conflict between the Vulcans, Andorians, and Tellarites had for the most part ended thanks to diplomatic intervention by United Earth and the starship Enterprise, under the command of Captain Jonathan Archer.
The Romulans saw this new-found peace in the region unacceptable, and thus began a carefully crafted campaign to destabilize the region and maintain the status quo of conflict between the quadrant's major powers.
At some point prior to 2154, a reunification movement began to become popular among some Romulan and Vulcan citizens. In that year, the Vulcan High Command, under the leadership of Administrator V'Las, planned to launch a preemptive strike against Andoria, citing that the Andorians were developing weaponry based on Xindi technology. Additionally, the Earth embassy on Vulcan was bombed prior to the attempted execution of these plans, prompting involvement by United Earth and Starfleet. Although V'Las's plans were halted and his involvement with the bombing was exposed, his connection with a Romulan operative who had been working on Vulcan with V'Las for several years, remained secret. (ENT: "The Forge", "Awakening", "Kir'Shara")
Later that year, the Romulans continued their campaign of destabilizing the Alpha Quadrant by sending automated drone ships to attack Andorian and Tellarite targets, with the hopes of provoking a war between the two powers. Unfortunately for the Romulans, this had the opposite effect of what they were hoping to achieve; instead of destabilizing and dividing the region, the attacks on United Earth, Vulcan, Andoria, and Tellar resulted in a successful allied effort to stop the drone ships and return peace to the region. (ENT: "Babel One", "United", "The Aenar")
In 2266, Spock categorized the weaponry generally used in the Earth-Romulan War as atomic in nature, and fairly primitive at that. He also characterized the ships in use as primitive, and designed in ways that did not permit quarter or captives.
Romulan starships were painted to resemble a "bird of prey", a tradition kept through the mid-23rd century. Ship-to-ship visual communication between Earth-allied ships and Romulan-allied ships did not take place during the war or during the peace negotiations.
The Battle of Cheron in 2160 is generally considered the decisive battle in the Earth-Romulan War. Both sides recognized the major victory achieved here by Earth and its allies as a humiliating defeat of the Romulan military. This event would establish long-term political effects within the Romulan Empire lasting well into the 24th century. (ENT: "In a Mirror, Darkly, Part II", TNG: "The Defector")
Despite the Romulan's 2154 campaign of destabilization and the war that followed, Earth and Romulus learned little of each other in the 22nd century. In fact it would be over a century before any Human would even see what a Romulan looked like. (TOS: "Balance of Terror")
Following the Battle of Cheron the two sides negotiated a treaty via subspace radio. Among other things, it established a Neutral Zone, entry into which by either side would constitute an act of war. Earth set up at least eight outpost stations on asteroids along its side of the Neutral Zone to monitor Romulan activity.
From a 23rd century Human perspective, the Neutral Zone represented an area "between planets Romulus and Remus and the rest of the galaxy..." Some Humans still harbored resentment over the war after over a century of peace, including Lieutenant Stiles of the USS Enterprise.
Despite these Human attitudes, until 2266 the Neutral Zone served its purpose and the treaty had remained unbroken. In fact, one might say it served its purpose too well, as there were limited or no contacts between Earth and the Romulan Star Empire from the conclusion of the war until the mid-23rd century. (TOS: "Balance of Terror")
|Earth wars prior to the Federation|
|Crusades • American Revolution • American Civil War • World War I • World War II • Brush Wars • Earth Cold War • Eugenics Wars • World War III • Earth-Kzin Wars • Earth-Romulan War|
The details of the Earth-Romulan War are still somewhat uncertain with little canonical evidence. As Spock said about the war, "As you recall from your histories, this conflict was fought, by our standards today, with primitive atomic weapons and in primitive space vessels which allowed no quarter, no captives. Nor was there even ship-to-ship, visual communication; therefore, no human, Romulan, or ally has ever seen the other. Earth believes the Romulans to be warlike, cruel, treacherous... and only the Romulans know what they think of Earth." The exact dates for the war and several details above are derived from an illegible viewscreen graphic seen in the Star Trek: Enterprise episode "In a Mirror, Darkly, Part II". The graphic was comprised of data points from an outdated version of the Star Trek Chronology.
Prior to this, a behind-the-scenes newspaper clipping titled It's Federation Day!, which was among the collection found in the Picard family album from Star Trek Generations, dated "11 Oct. 2161," stated that the war ended "a little more than a year" prior to the final declaration of peace and the foundation of the Federation. This source also stated that the war ended with the Battle of Cheron in early 2160. This information did not appear on screen.
Some evidence indicates that Earth itself commenced the conflict, as Data remarked in "The Defector" that "in their long history of war, the Romulans have rarely attacked first... they prefer to test their enemy's resolve." In other words, Earth may have been provoked into acting first, either intentionally or possibly inadvertently. However it may have been one of the few occasions that the Romulans did attack first, such as the events that transpired in "Balance of Terror."
The Star Trek: Enterprise series finale "These Are the Voyages..." presents the formation of an alliance that in the words of Deanna Troi, "will lead to the founding of the Federation." It is unclear whether or not this "alliance" was the one spoken of between Earth and its allies during their opposition against the Romulans as Troi made no mention of the Earth-Romulan War itself.
The fourth season of Enterprise began to show the very early beginning of the coming conflict with the Romulans. Had Enterprise been renewed for a fifth season, it would have continued to show the whispers of the Romulan War and eventually allow the conflict to be realized on screen. Additionally, Rick Berman and Brannon Braga considered making "Future Guy" a Romulan. 
In the Star Trek Star Fleet Technical Manual, Franz Joseph offered a one-page version of the subspace peace treaty that concluded the war. It was signed by "Christofur Thorpe" for Earth and "Praetor Karzan" for the Romulans.
There are several points of ambiguity involved with this time period. For more information on those topics please visit the following links: cloaking device, Romulan Bird-of-Prey (22nd century) and Romulan Bird-of-Prey (23rd century).
In the Spaceflight Chronology, more detailed accounts are given of the events that led to the war and the war itself. 14 years prior to the actual war, the Romulan Star Empire began a campaign of attacks disguised as random space pirate activity. The first of these attacks was the hijacking of the ore freighter USS Muleskinner. Two years later the Delta VII outpost was attacked. Five years after this, the commercial transport Diana was attacked with its cargo stolen and crew killed. Four years prior to the actual war, the reports on piracy attacks were for the first time percieved as possibly being organized. Three years before the war, Starbase 1, in Sector 3A, was destroyed by what was still believed to be an act of space piracy. Romulans were for the first time identified as the culprits. All transports were given military escorts at this time. Two years before the war, the Romulan threat became apparent. A year before the war, Romulans made a number of hit and run attacks to several sectors. The actual war began when a full Romulan invasion fleet advancing on the Rigel system was encountered by the destroyer USS Patton. In the second year of the war, Romulans managed to destroy a mining complex in Sector 5B. A Romulan armada was completely destroyed in Sector 7. In the third year of the war, Romulans attacked Alpha Omega. Victory in the war was credited to advanced ship-mounted laser weaponry, developed only two years before the war as a response to the destruction of Starbase 1.
The dates of these events in the timeline of the Spaceflight Chronology differ from the canonical timeline. Also, the major difference between these accounts and canonical accounts is that the war is stated to have been fought by the Federation, not the allied forces as was established later on in the viewscreen graphic from "In a Mirror, Darkly, Part II".
The Pocket ENT novel Last Full Measure suggests that the Federation was born from the conflict. The Last Unicorn Games book Among the Clans: The Andorians makes reference to a series of Earth-Romulan wars, taking place during roughly the same time as the single canonical war.
In DC Comics's The Mirror Universe Saga the conflict marks the point of divergence: Earth lost the war, was occupied by the Romulans, and the resistance which eventually fought them off took control of the planet and proclaimed that Humanity would now be the conquerors, not the conquered. This contradicts the established canon as the Star Trek: Enterprise episodes "In a Mirror, Darkly" and "In a Mirror, Darkly, Part II" show that the divergence occurred well prior to the launch of Enterprise NX-01.
In the 2006 game Star Trek: Legacy it is revealed that a Vulcan scientist named T'Uerell supplied the Romulan Star Empire with metagenic weapons to use against Earth colonies. Earth used the radiation from nuclear reactors in the Tyburn system to halt a large Romulan force from reaching Earth – explaining the use of atomic weapons.
The Pocket ENT "relaunch" arc by Michael A. Martin starting with The Good That Men Do covers the events from the end of Enterprise to the Romulan war. It starts with the apparent death of Trip so he can spy on the Romulans attempt to create a warp-seven capable ship. This reinterprets the events shown in "These Are the Voyages...", moving them to 2155. According to the series, the Romulans started the war out of fear of the birth of the Coalition of Planets, by attacking proposed member Coridan (thus delaying their entrance into the alliance until The Original Series and then by attacking a number of Coalition ships using a telecapture device and destroying the Kobayashi Maru as seen in the novel Kobayashi Maru. The novel series Star Trek: Enterprise - The Romulan War details the war proper.