(covers information from several alternate timelines)
Vulcans were once an extremely violent and emotional people, waging almost constant warfare upon one another. (TOS: "Balance of Terror"; ENT: "The Forge") As their technology improved, the Vulcans eventually reached a point where their violent nature threatened the extinction of their species. (ENT: "Awakening"; TNG: "Gambit, Part II") Around 370 AD, the philosopher Surak led his people in a great reformation to embrace logic and pacifism, a period called the Time of Awakening. One group, known as "those who march beneath the Raptor's wings", rejected Surak's teachings and fought against his followers. (TOS: "The Savage Curtain"; TNG: "Gambit, Part II"; ENT: "Awakening") At the end, the dissidents lost a terrible atomic war that ensued and left their homeworld. During their travels, some split away to form the Debrune civilization, which became extinct long before the 24th century. Eventually, the group settled on two planets named Romulus and Remus, and thus laid the foundation of the Romulan civilization. (TNG: "Unification I", "Gambit, Part I")
According to Admiral Dougherty, it was warp drive that turned "a bunch of Romulan thugs into an empire." Dougherty likened the impact of warp technology on the Romulans to that of petroleum on "petty thugs" on Earth in the past. (Star Trek: Insurrection)
The Romulan Empire's first recorded contact with Humans occurred in 2152, when the Starfleet vessel Enterprise NX-01 was on course to explore an M-class planet. Unknown to Enterprise, the planet was claimed by the Romulans and the ship was damaged by a cloaked spatial mine, part of a minefield surrounding the planet. A decloaking Romulan Bird-of-Prey subsequently established audio communication and, although the universal translator initially had problems to lock on to the Romulan language, Enterprise communications officer Hoshi Sato was able to translate what turned out to be an ultimatum to depart immediately. After successfully detaching a spatial mine that latched on to the ship's hull, Enterprise left the system. (ENT: "Minefield")
As of 2154, the Romulan Star Empire was collaborating with Administrator V'Las of the Vulcan High Command as part of a decades-long effort to "reunify" the Romulan and Vulcan "cousins", presumably under Romulan rule. However, a group of Vulcans named Syrrannites accused the High Command of no longer following the logical teachings of Surak and, thus, were a threat to the Romulan plans of reunification. Secretly working with Major Talok, a Romulan deep-cover agent who had infiltrated Vulcan several years earlier and now worked within the Vulcan High Command, V'Las assumed a very aggressive stance and framed the Syrrannites for a terror attack on the United Earth Embassy on Vulcan. Also calling for a preemptive strike against Andoria, the conspiracy ultimately led to the Battle of Andoria between Vulcan and the Andorian Empire in mid-2154. However, V'Las was deposed after he was eventually identified as being behind the embassy bombings and the exaggerated war claims against the Andorians. Although Talok then promised to him that this would be but a minor setback, he subsequently left Vulcan. (ENT: "The Forge", "Kir'Shara")
As it was mainly due to the Earth starship Enterprise and its crew that the Romulan plot had been thwarted, it became more evident for the Star Empire that the Humans were rising as a regional power. United Earth practiced a mediating, even unifying, influence on its neighbors, so the prospect of an alliance contrary to Romulan interests led to their covert attempts to destabilize the region and the fragile peace. Therefore, Admiral Valdore, with the support of Senator Vrax, precipitated the "Babel Crisis" by deploying telepresence-operated drone ships equipped with chameleon-like camouflage systems. Though briefly wreaking havoc on regional shipping and diplomacy, the Romulan effort ultimately failed. A temporary alliance of Human, Vulcan, Andorian and Tellarite starships thwarted the drone ship threat, prompting closer diplomatic relations that led to talks, in 2155, on forming a Coalition of Planets. (ENT: "Babel One", "United", "The Aenar", "Demons")
Relations between Romulans and United Earth deteriorated into open war in the following years. Beginning in 2156, the Earth-Romulan War was fought without any kind of personal or visual interaction between the two sides, preventing Humans or allies from fully understanding the nature of their opponent. Following a humiliating defeat at the Battle of Cheron in 2160 at the hands of a Human/Vulcan/Andorian/Tellarite alliance, the Romulans agreed to a treaty establishing a neutral zone between the Star Empire's sphere of influence and territory that would fall under the jurisdiction of the soon-to-be-formed United Federation of Planets. (ENT: "In a Mirror, Darkly, Part II", TOS: "Balance of Terror"; TNG: "The Defector")
For the next century, Romulans isolated themselves from Human and Federation affairs. However, they remained very active within their own sphere of influence, fighting numerous campaigns. (TOS: "Balance of Terror")
In 2266, the Neutral Zone Incursion by the Romulan Star Empire marked the end of a century of isolation. Emerging from seclusion to test the strength of its old enemy as well as to field test new technologies of its own, the Romulan Praetor ordered his finest flagship, a Romulan Bird-of-Prey led by an experienced commander, to violate the Neutral Zone and attack a series of Federation outposts that lined the border, in Sector Z-6. Equipped with a cloak and a powerful new plasma torpedo system, the Bird-of-Prey easily annihilated Outposts 2, 3, 4, and 8. A victorious homecoming, revealing Federation weaknesses, would have aroused the Empire to another war, but the marauding Romulan vessel was intercepted and defeated by the USS Enterprise before success could be reported.
The incident ended with a visual communication in which the Romulan Commander bestowed his respect to Captain Kirk of the Enterprise. This also marked the Federation's first confirmed visual observation of the Vulcan-like Romulan appearance. (TOS: "Balance of Terror")
A brief but ultimately unsuccessful thawing in relations occurred in 2267 between the Romulan Star Empire, the Klingon Empire, and the Federation, with the founding of a jointly managed colony on Nimbus III. Dubbed the "planet of galactic peace," the colony quickly became an embarrassing failure for all three governments, although regular meetings between representatives did take place at the colony for at least the next twenty years. (Star Trek V: The Final Frontier)
In 2268, a devastating polaric ion device explosion resulted in the destruction of a Romulan research colony on Chaltok IV. Following this incident, the Polaric Test Ban Treaty, banning research on polaric energy, was signed. (VOY: "Time and Again")
Within that same year, Captain Kirk was ordered to take the Enterprise into the Neutral Zone, thereby provoking an encounter with Romulan forces in an attempt to steal a functional cloaking device. The Star Empire was now using starships of Klingon design. The Enterprise was quickly intercepted and detained by three Romulan vessels. By faking his death, Kirk was able to infiltrate one of the Romulan ships, steal their cloaking device, and subsequently use it on the Enterprise to escape to Federation space along with a captured Romulan commander. (TOS: "The Enterprise Incident")
Whatever kind of cooperation might have been indicated by the Romulans employing a Klingon ship design in 2268, it had likely come to an end by 2271, when the Romulans suffered a significant defeat at the Battle of Klach D'kel Brakt (the "Briar Patch") at the hands of Klingon forces led by Kor. By the mid-2280s, the Romulan Star Empire apparently lost its unique tactical advantage, when Klingon vessels began to use cloaking devices, too. By 2292, Romulans and Klingons regarded each other as "blood enemies." (TOS: "The Deadly Years", "The Enterprise Incident"; TNG: "Reunion"; DS9: "Blood Oath"; Star Trek III: The Search for Spock; Star Trek: Insurrection)
In 2293, the destruction of the Klingon moon Praxis caused an ecological and economical disaster in the Klingon Empire, bringing about a fundamental shift of power in the quadrant. When the Chancellor of the Klingon High Council, Gorkon, took the controversial move of proposing a full peace treaty with the Federation, the Romulan government, while officially remaining neutral, attempted diplomatic subterfuge to prevent such an unfavorable situation. The Romulan Ambassador to Earth, Nanclus, became part of a conspiracy, which also included conservative members of Starfleet as well as the Klingon Empire, and cautiously tried to escalate the situation by advising the Federation President to execute Operation Retrieve. Although the conspiracy was able to assassinate Chancellor Gorkon, it was ultimately uncovered and unsuccessful in sabotaging a lasting Federation-Klingon peace treaty. (Star Trek VI: The Undiscovered Country)
Aggressions and espionage against the FederationEdit
Intermittent hostilities between the Romulan Star Empire and the Federation continued into the 24th century. A notable example was the Norkan Campaign led by Admiral Alidar Jarok, which the Federation considered to be a massacre. (TNG: "The Defector"). In 2311, the Tomed Incident between the Romulans and the Federation cost thousands of lives and led to the Treaty of Algeron, which set the foundation for a lasting period of peace. The Treaty forbade the Federation from developing cloaking technology and clarified that violations of the Romulan Neutral Zone without adequate notification, by either side, would be considered an act of war. The Empire subsequently returned to a policy of isolation from the Federation, turning their attention to "matters more urgent." (TNG: "The Neutral Zone", "The Defector", "The Pegasus")
The Romulans began emerging from their isolation in 2364. First, a Federation border outpost reported that seven Romulan battle cruisers had entered sensor range, prompting a response by the USS Berlin. (TNG: "Angel One") Later that year, a warbird under Commander Tebok was dispatched to investigate the mysterious destruction of border outposts along either side of the Neutral Zone. Tebok confronted Captain Jean-Luc Picard of the USS Enterprise-D on the Federation side of the Neutral Zone. It was determined that neither side had been responsible for the attacks, which unknown at the time were caused by the Borg. After 53 years, 7 months, and 18 days of no official contact, the Empire subsequently resumed an active, oppositional interest in Federation affairs. (TNG: "The Neutral Zone")
In 2366, the Romulan scoutship Pi crash-landed on Galorndon Core in Federation space. The Enterprise investigated the wreck and initially rescued one survivor, Patahk. Commander Tomalak, claiming the crash of the Pi to be an accident, demanded Patahk's return and eventually crossed the Neutral Zone to retrieve him. The incident nearly escalated to war after Patahk died of his injuries, but was defused after the Enterprise recovered and repatriated a second Romulan survivor, Centurion Bochra. (TNG: "The Enemy")
Later that year, the Neutral Zone was again violated by a scoutship piloted by Admiral Alidar Jarok. Jarok's intent was to defect to the Federation, so as to avert an impending Romulan invasion that was to be launched from a secret base on Nelvana III. Jarok had in fact been a victim of a misinformation campaign by Tomalak, who aimed to expose him as a traitor and lure the Enterprise into the Neutral Zone so that it could be captured. With the timely intervention of hidden Klingon reinforcements, the Enterprise was able to withdraw from the situation. (TNG: "The Defector") By 2367, Romulan forces were deployed in an aggressive posture along the Neutral Zone, which Starfleet believed was to support a strategy of testing Federation defenses. An overture to discuss the normalization of diplomatic relations between the two powers that year was found to be a Romulan ruse to extract one of their deep-cover operatives from Federation space. (TNG: "Data's Day")
Hot and cold conflicts with the Klingon EmpireEdit
The relationship between the Romulan and Klingon Empires was effectively a decades-long "hot" and "cold" war between bitterly antagonistic peoples, in spite of periods of titular alliance between the two powers. (TNG: "The Neutral Zone") In 2344, four Romulan warbirds attacked the Klingon outpost on Narendra III. The USS Enterprise-C, answering the Klingons' distress call, fought a futile defense against the Romulans and was also destroyed. Ironically, the self-sacrifice of the Enterprise reversed the trend of deteriorating relations between the Federation and the Klingon Empire, to the Romulans' detriment. (TNG: "Yesterday's Enterprise") Two years later, in 2346, at a time when it was supposed to be "an ally" of the Klingons, the Star Empire attacked the Klingon planet Khitomer and killed almost all of the 4,000 colonists. The raid was made possible by the traitor Ja'rod of the House of Duras, who supplied the Romulans with the deactivation codes of the colony's defensive shields. (TNG: "The Neutral Zone", "Sins of the Father")
In 2350, Romulan forces failed in an attempt to board Klingon General ShiVang's flagship. That same year, later Romulan Praetor Neral's family were killed in a Klingon attack. (DS9: "Once More Unto the Breach", "Inter Arma Enim Silent Leges")
In 2367, the Romulans engaged in concerted efforts, led by Commander Sela, to break the Federation-Klingon alliance and shift the balance of power in the quadrant in their favor. (TNG: "The Mind's Eye", "Redemption") The influential House of Duras, with its long-standing ties to the Romulans, provided the best opportunity as Duras was the favored candidate to succeed the ailing Chancellor K'mpec as leader of the Klingon Empire. After K'mpec's death, Romulan equipment was involved in Duras's attempt to assassinate his rival Gowron during the Rite of Succession. However, Duras was killed by Lieutenant Worf in vengeance for the murder of Ambassador K'Ehleyr. (TNG: "Reunion")
In another plot, the Romulans attempted to foment rebellion on the Klingon colony of Krios and blame it on the Federation. The Romulans supplied counterfeit Federation phasers to the Kriosian rebels and abducted Lt. Commander Geordi La Forge, whom they brainwashed to assassinate Vagh, the Klingon governor of Krios. Enterprise personnel were able to prevent the assassination and expose the Romulans' involvement. (TNG: "The Mind's Eye")
Near the end of 2367, the Romulans secretly backed Lursa and B'Etor's bid to take over the Klingon Empire via Duras's illegitimate son Toral. In the ensuing Klingon Civil War, Romulan supplies enabled the forces of the Duras sisters to make advances against those of Gowron. Captain Jean-Luc Picard suspected Romulan interference in the war and led a fleet of 23 starships to blockade the Klingon-Romulan border. Through the efforts of Lt. Commander Data on the USS Sutherland, a convoy of Romulan supply ships was exposed, forcing Sela to order her ships back to Romulan territory. Without Romulan support, the Duras sisters lost the war and were forced to flee. (TNG: "Redemption")
There had long existed an underground movement of Romulans interested in Vulcan culture and philosophy, who desired to eventually reunite with their distant cousins. Despite being declared enemies of the state, the unification movement grew in strength during the 24th century. The cause of unification appeared to near a breakthrough in 2368 with the rise of Proconsul Neral, who seemed receptive to the possibility of unification. Senator Pardek, a long-time ally of the unification movement, invited Ambassador Spock to Romulus to address the opportunity for peace.
However, Pardek had in fact betrayed the unification movement at the behest of Neral and Commander Sela. Sela sought to use the unification movement and Spock's credibility to disguise an attempted invasion of Vulcan using three stolen Vulcan transports. Spock, Captain Jean-Luc Picard, and Lt. Commander Data managed to expose the conspiracy, leading the Romulans to destroy their invasion force rather than allowing their capture by Starfleet. (TNG: "Unification II") Spock remained on Romulus to support the underground movement. In 2369, he arranged for the defection of Vice-proconsul M'ret, who had spoken out against the repressive policies of the Romulan government, to the Federation. (TNG: "Face of the Enemy")
The Romulans encountered personnel from the Federation starship USS Voyager, stranded in the Delta Quadrant, on two occasions. Lieutenant Reginald Barclay would claim in 2377 that the Romulans have "been interested in Voyager for years". (VOY: "Inside Man")
In 2351, the science vessel Talvath, commanded by Dr. Telek R'Mor, came into contact with the USS Voyager twenty years in the future through a micro-wormhole in Sector 1385. R'Mor agreed to deliver letters from the Voyager crew to their families at the appropriate time, but due to his death in 2367 he was unable to do so. It was, however, remarked that the data chip R'Mor was given possibly passed on to other Romulan officials, therefore precipitating a certain knowledge of Voyager and its fate. (VOY: "Eye of the Needle", "Message in a Bottle") Voyager was also responsible for the failure of a 2374 Tal Shiar operation, led by Rekar, to steal the experimental USS Prometheus. The Voyager crew had transmitted their EMH through the Hirogen communications network to the Prometheus in an attempt to communicate with Starfleet. Once aboard, the Voyager EMH cooperated with the Prometheus EMH Mark II to incapacitate the Romulans and assist a Starfleet task force in reclaiming the ship. (VOY: "Message in a Bottle")
- Main article: Dominion War
In late 2370, contact with the Dominion, a hegemonial power from the Gamma Quadrant ruled by the "Founders", led to the first thaw in the Star Empire's relations with the Federation. The Romulans regarded the Dominion as the greatest existential threat to emerge in the past century, but were unwilling to send any ships to the Gamma Quadrant via the Bajoran wormhole themselves. Instead, in exchange for intelligence gathered regarding the Dominion, in 2371 the Romulans permitted the use of a cloaking device on the USS Defiant, which was to be used only in the Gamma Quadrant and operated and guarded by a a Romulan liaison officer. Some months later, two official Romulan diplomats, Ruwon and Karina, as well as a secret, cloaked warbird, were dispatched to Deep Space 9, the Bajoran-Federation space station at the mouth of the Bajoran wormhole. The diplomats were unimpressed with the eventual intelligence data they were provided with and suspicious of the station's security chief Odo, failing to see the distinction between "Changeling" and "Founder". In fact, the entire diplomatic mission was but a cover to carry out the actual Romulan plan - to end the Dominion threat by using the warbird to destroy the wormhole along with Deep Space 9 in order to discard of any witnesses. However, the ploy was uncovered as the cloaked warbird was discovered and Ruwon and Karina had to leave the station. (DS9: "The Search, Part I", "Visionary")
Nevertheless, through their agreement with Starfleet, the Romulans had already learned of the Founders, their control of the Jem'Hadar through ketracel-white, and the location of their homeworld. (DS9: "The Die is Cast") Still poised to end the Dominion threat once and for all, the Romulan intelligence service Tal Shiar conspired with the Cardassian Obsidian Order to launch a joint attack on the Founder's homeworld in the Omarion Nebula. By annihilating the Founders, it was estimated that the Jem'Hadar would weaken and die out in a matter of days as their supply of ketracel-white would run out. However, the Tal Shiar had been infiltrated by a changeling agent, who had actually supported the plan as a unique opportunity to wipe out or substantially weaken the Tal Shiar as well as the Obsidian Order - ruthless organisations with the potential of being a threat to the Dominion. The resulting battle in the Omarion Nebula proved catastrophic for both fleets, and although a small number of Romulans survived and was imprisoned at Internment Camp 371, all five Romulan warbirds involved in the battle were destroyed. (DS9: "The Die is Cast", "In Purgatory's Shadow")
When the Dominion gained a major foothold in the Alpha Quadrant through the incorporation of the Cardassian Union in 2373, the Romulans dispatched a fleet of warbirds to Deep Space 9 in anticipation of an imminent Dominion attack, joining the Klingon and Federation forces there. (DS9: "By Inferno's Light") However, after war did not immediately break out, the Romulan Senate eventually opted to sign a non-aggression pact with the Dominion. (DS9: "Call to Arms") The pact was negotiated by Senator Vreenak, who remained an ardently pro-Dominion voice in the Romulan government. (DS9: "In the Pale Moonlight")
The Romulans thus did not participate in the early months of the Dominion War, though some analyses suggested that they would eventually join the war against the Dominion. (DS9: "Statistical Probabilities") Nevertheless, the Romulans were turning a blind eye to Dominion forces crossing their space to ambush Federation ships. Concluding that the war could not be won without Romulan involvement, Captain Benjamin Sisko and Elim Garak undertook a covert operation to convince the Romulans that the Dominion posed an imminent threat. To that end, Vreenak was presented with an optolythic data rod containing a forged holographic record of a secret meeting showing Dominion officials Weyoun and Legate Damar discussing an invasion of the Romulan Empire. Although Sisko hoped the fake recording would pass and convince the Senator, an infuriated Vreenak uncovered the plot and headed back to Romulus. However, the operation ended with the assassination of the Senator by sabotaging his shuttle. As Garak had originally foreseen, the Romulans discovered the data rod, but ascribed any imperfections to the blast damage, and therefore blamed the Dominion for the assassination. (DS9: "In the Pale Moonlight")
In the wake of Vreenak's death and the discovery of apparent Dominion invasion plans, the Romulan Star Empire formally declared war, joining the Federation Alliance. Within hours, Romulan forces attacked fifteen bases along the Cardassian-Romulan border, opening up a new front and relieving pressure on the Federation and Klingon lines. (DS9: "In the Pale Moonlight") Further Romulan engagements soon followed, including the liberation of the Federation world Benzar, which had earlier been occupied by the Dominion (DS9: "The Reckoning"), as well as twelve successful campaigns led by Shinzon of Remus. The Romulans often employed Reman shock troops in the most violent encounters. (Star Trek Nemesis)
The Romulans soon sent representatives, first Senators Letant and Cretak, then General Velal, to coordinate war plans with their new allies, and eventually established a permanent presence on Deep Space 9. (DS9: "Image in the Sand") Interactions between the formerly adversarial powers though remained fractious, and the Federation was often forced to mediate disputes between the Romulans and the Klingons. (DS9: "Tears of the Prophets") At one point, an attempt by the Romulans to place heavy weapons on the Bajoran moon Derna nearly shattered the alliance. (DS9: "Shadows and Symbols") In general, however, diplomatic relations between the Romulans and the Federation improved during the war. In 2375, the Federation embargo on Romulan ale was lifted, and a Romulan-Federation conference took place on Romulus. On the other hand, both sides were aware that they would be rivals for influence in the quadrant once the Dominion was defeated. Espionage and covert operations were rampant, including an effort by Starfleet and Section 31 to place a Federation agent on the powerful Romulan Continuing Committee. (DS9: "Inter Arma Enim Silent Leges")
Romulan forces were involved in most major battles in the later parts of the Dominion War, including the first and second battles in the Chin'toka system as well as the final push against Cardassia Prime. The latter saw the destruction of the Romulan flagship and was pushed for by the Federation and the Klingon Empire, despite an initial hesitation of Romulan representative Velal, who thought it would be wiser to contain the Dominion, rather than to mount a major offensive. (DS9: "Tears of the Prophets", "The Changing Face of Evil", "The Dogs of War", "What You Leave Behind") After the Federation Alliance's victory at Cardassia in late 2375, a female Romulan dignitary represented the Star Empire at the signing of the Treaty of Bajor on Deep Space 9, which formally brought the Dominion War to a conclusion. (DS9: "What You Leave Behind")
Reman coup d'étatEdit
Following the Dominion War, Romulan-Federation relations cooled off again, a minor side-effect being the reintroduction of the ban on Romulan ale in the Federation, which had temporarily been lifted during the war. By 2379, a schism had developed between the Romulan Senate and the military over whether the Empire should seize the opportunity to invade the Federation. During this time Shinzon, a Human clone of Captain Jean-Luc Picard, emerged as the leader of a powerful Reman force wielding new technologies, including an improved cloaking device and a thalaron radiation weapon. Shinzon enlisted the support of Commander Suran and Senator Tal'aura by promising to conquer Earth. After Praetor Hiren rejected Suran's proposal to ally with Shinzon, as expected, Tal'aura planted a thalaron radiation device that assassinated the rest of the Senate.
Shinzon installed himself as the new Praetor and invited the USS Enterprise-E to Romulus for peace talks. However, his gesture was a mere ruse for the purpose of capturing Picard, as he needed a transfusion from Picard to heal his rapidly deteriorating body. Picard and the Enterprise escaped, pursued by Shinzon aboard his flagship Scimitar, while Commander Donatra was able to convince her superiors that they could not support Shinzon's genocidal ambitions. Donatra led two warbirds in support of the Enterprise during its battle with the Scimitar in the Bassen Rift. Ultimately, Shinzon and the Scimitar were both destroyed. The successor Romulan government made genuine overtures of peace toward the Federation, which was hoped would usher in a new era of understanding and peace between the two powers. The USS Titan was subsequently dispatched to the Romulan Neutral Zone to serve as the command ship for a diplomatic task force. (Star Trek Nemesis)
In 2387, a nearby star went supernova and threatened Romulus with annihilation. Ambassador Spock pledged to save Romulus by using red matter to create a black hole that would absorb the explosion. Unfortunately, he arrived too late to prevent the destruction of Romulus, and billions of lives were lost. (Star Trek)
In an alternate future created by Q's manipulations, the Romulans were defeated by the Klingon Empire. Their territory was occupied by the Klingons, and the Neutral Zone abolished. This timeline was avoided by the actions of Jean-Luc Picard. (TNG: "All Good Things...")
In an alternate timeline caused by the USS Defiant accidentally sending three officers into Earth's past, the Federation never came to be. When the crew of the Defiant in 2371 scanned for Federation and alien outposts, all they could find were Romulan transmissions detected in the vicinity of Alpha Centauri. (DS9: "Past Tense, Part I")
In the alternate reality created by Nero, by 2258, the Federation had become aware of the Romulans' common ancestry with the Vulcans. The alternate Nyota Uhura was knowledgeable on all three dialects of their language. (Star Trek)
Summary of key datesEdit
- 370: Time of Awakening on Vulcan – As the planet is consumed by atomic wars, Surak proposes to embrace logic as a way to peace. "Those who march beneath the Raptor's wings" oppose his views and leave the planet after losing the war. Some become the ancestors of the Debrune, while others settle Romulus, laying the foundation of the Romulan civilization.
- 2152: First contact with Humans occurs as the Earth Starfleet vessel Enterprise NX-01 accidentally enters a Romulan minefield protecting a planet claimed by the Star Empire.
- 2154: The Romulan Star Empire has infiltrated the Vulcan High Command in an effort to facilitate an eventual re-unification of both peoples. Under this influence, Vulcan Administrator V'Las assumes a very aggressive stance towards the Andorians and openly persecutes the Syrrannite-sect, which believes Vulcan is no longer following the true, pacifist teachings of Surak. With the help of Enterprise NX-01 amongst others, V'Las is eventually deposed, after which his Romulan contact on Vulcan departs. Later that year, Admiral Valdore launches two remote-controlled drone ships with holographic disguises in order to prevent further rapprochement between the Humans, Vulcans, Andorians and Tellarites. Although the ships wreak havoc and provoke a diplomatic crisis between the Andorians and the Tellarites, the mission ultimately fails and even leads to closer cooperation between the Humans and their neighbors.
- 2156-2160: The Earth-Romulan War – the conflict with the Humans escalates into an open war, which is concluded with a humiliating defeat for the Romulans at the hands of an Earth/Vulcan/Andorian/Tellarite alliance at the Battle of Cheron. Via subspace radio and completely without any visual communication, a neutral zone between the two power blocs is agreed on and the Star Empire begins a period of isolation from the other side, i.e., the soon-to-be-formed Federation.
- 2266: The Star Empire emerges from seclusion as the Romulan Praetor orders to test the strength of the Federation by dispatching his flagship, equipped with a cloak amongst its arsenal, to violate the Neutral Zone. Although it destroys Federation Outposts 2, 3, 4, and 8 in Sector Z-6, the vessel is defeated by the USS Enterprise and the first official visual communication between both sides confirms the Vulcan-like physical appearance of the Romulans.