Troyius was the fifth planet of the Tellun system in the Alpha Quadrant. It was the homeworld of the Troyian people, and a rich source of dilithium. (FASA RPG module: The Orions: Book of Common Knowledge, Decipher RPG module: Worlds)


Troyius was a monarchy ruled by a Prefect-King (FASA RPG modules: The Federation, The Orions: Book of Common Knowledge) or Principus (Decipher RPG module: Worlds). In 2268, this was Cosalthan II, who married Dohlman Elaan of Elas. The two then ruled both of their worlds jointly. Beneath them was a system of nobility and actone (FASA RPG module: The Orions: Book of Common Knowledge), as well as the Troyius Tribunal. (TOS episode: "Elaan of Troyius")

The FASA RPG's The Federation has Elaan marry "the son of Troyius's current ruler", while The Orions: Book of Common Knowledge says she married "the Prefect-King of Troyius, Cosalthan II". Meanwhile, the ST reference: Star Trek Maps says she married "the Troyian Prefect", which may be the same as the Prefect-King, or perhaps a lesser, prince-like role. The Decipher RPG's Worlds has her marry "the Principus of Troyius". These do not necessarily contradict; taken together, it seems likely that the Prefect/Principus is the son of the Prefect-King, or another name for the position, and Cosalthan II became king shortly before, during or shortly after his marriage to Elaan. Finally, the TOS novel: Firestorm instead states that Elaan was married to Bejas, the leader of Troyius.

Troyius joined the Federation shortly after contact in 2258 (Decipher RPG module: Worlds), and was an associate member by reference stardate 2/2306.01 (circa 2287) (FASA RPG module: The Federation). By the late 24th century, Troyius was still a member of the United Federation of Planets. (Star Trek: Destiny novel: Lost Souls) Troyius, like Elas and the rest of the Tellun system, was of continuing political and military value to both the Federation and the Klingon Empire, for its dilithium supply (FASA RPG module: The Federation). Peace in the Tellun system, between Troyius and Elas, was therefore a matter of great importance. (Decipher RPG module: Worlds)


The capital city of Troilus was home to a spaceport constructed in the late 23rd century. There was also the Interplanetary Bazaar, a huge market that enabled the trade of goods such as dilithium, though in limited quantities and strictly controlled by the government. (FASA RPG module: The Orions: Book of Common Knowledge)

Troyius was also home to an Orion Colony of many fine and beautiful cities, dating back to before the sacking of the world by Half-a-Man Sooris and his pirate fleet. After this, the Orions were never able to ingratiate themselves with the Troyians or join their society. (FASA RPG module: The Orions: Book of Common Knowledge)

Both Orions and Troyians are known for their green skin. The placement of an Orion Colony on this world may have been intended to suggest a shared heritage, but the source gives no indication of this, and even separates the two communities.

It had a technological/sociopolitical index of 668877-75 and a planetary trade profile of ABCBCCB/D(C) (FASA RPG module: The Orions: Book of Common Knowledge). Its major concerns were cultural. As of reference stardate 2/2306.01, it had a population of 3.58 billion. (FASA RPG module: The Federation)


Troyius was a Class M world with 2 moons, a thin atmosphere and a cool but comfortable temperate climate, with a lush environment. It had a gravity of 0.9 g and a 22.75-hour day. It had a total surface area of 1,040,676,000 square kilometers, and with 35% land mass, total land area of 364,236,600 square kilometers. Its makeup consisted of 12% normal metals, 15% industrial crystals, and 10% special minerals, with trace amounts of radioactive elements and gemstones. (FASA RPG module: The Orions: Book of Common Knowledge)

The FASA RPG modules: The Federation, The Orions: Book of Common Knowledge have the same diameter but give different figures for equatorial circumference and surface areas. The numbers from The Orions are mathematically correct and have been used here. The Federation also states a 55% special mineral content.

The planet was rich in natural resources, with valuable heavy metals, mineral deposits, and great quantities of dilithium crystals. (FASA RPG module: The Federation, Decipher RPG modules: Aliens, Worlds)


At some point in its past, Orions came to Troyius and constructed a Colony there. It became one of their most productive worlds. (FASA RPG module: The Orions: Book of Common Knowledge)

The notorious Orion pirate Half-a-Man Sooris led his massive pirate fleet, the largest in history, in the devastating sacking of the Tellun system, beginning on the 19th February, 1894 CE (reference stardate −2/9402.19) and lasting for weeks. The pirates outnumbered the defenders, and many Orion Colony crews mutinied to return and defend their homes. The Orion Colony on Troyius was temporarily abandoned, and over 2.5 million people died, including 1.5 million Orions. Civilization was all but wiped from its surface. The incident ruined relations between Orions and Troyians. (FASA RPG modules: The Orions: Book of Common Knowledge, The Orions: Book of Deep Knowledge)

Some believed that the Troyians were descendants of a lost Andorian colony. (FASA RPG module: The Federation)

The Federation makes Troyians blue-skinned with no mention of antennae, and has the first Andorian colonization of another world occur in stardate −1/96 (1996), though this may also be a transplantation by the Preservers or another race. It is not clear, then, who else lived on Troyius at the time of the Sooris sacking, but these theories may be in error.

In the 22nd century, the Troyians developed interplanetary travel, before or around the same time as the neighboring Elasians. As soon as the two races became aware of one another, relations developed into rivalry and quickly into war. (ST reference: Star Trek Maps, Decipher RPG module: Worlds)

The complete story of how the war began was still being pieced together by historians and diplomats of the late 23rd century. The battles were fought with relatively crude interplanetary spacecraft, lasers and atomic weapons, all in a major interplanetary war for control over the Tellun system. (FASA RPG modules: The Orions: Book of Common Knowledge, The Federation)

The war continued on into the mid-23rd century. Both powers made contact with the Federation in 2258, and soon after became members, but continued to skirmish with each other. (Decipher RPG module: Worlds) By this time, the Troyians had managed to fight the Elasians to a draw. (FASA RPG module: The Federation)

Meanwhile, Federation scientists conducted a geological survey of Troyius, and discovered the world’s rich stores of valuable heavy metals, mineral deposits, and dilithium crystals. Suddenly, Troyius became a world of significant strategic importance. (Decipher RPG modules: Aliens, Worlds) The Federation then intervened in the conflict, sending a number of negotiators to mediate and broker a peace. Finally, a truce was declared. (FASA RPG modules: The Orions: Book of Common Knowledge, The Federation, Decipher RPG modules: Aliens, Worlds)

In 2268, the peace negotiations resulted in an arranged marriage between Cosalthan II of Troyius and Dohlman Elaan, daughter of the Elasian ruling family, in hopes of ending the hostilities. (FASA RPG modules: The Orions: Book of Common Knowledge, The Federation, Decipher RPG module: Worlds)

The USS Enterprise was sent to serve as ambassador, aiding peace negotiations and escorting Elaan to Troyius for the marriage. Despite Klingon interference, Elasian sabotage and Elaan's reluctance, the mission was successful. (TOS episode: "Elaan of Troyius")

The centuries of war ended with the marriage of the Cosalthan and Elaan; the pair went on to jointly rule both their worlds (FASA RPG module: The Orions: Book of Common Knowledge)

Though Klingons made further attempts to disrupt the peace and gain access to the dilithium deposits, the Tellun system remained stable. (FASA RPG module: The Federation)

In the twenty years after Federation contact, Troyius flourished and prospered thanks to its influence. Troyius committed itself to developing interstellar trade, and the merchant fleet was improved. A modern spaceport was constructed at the capital of Troilus, and the Interplanetary Bazaar enabled the trade of goods. (FASA RPG module: The Orions: Book of Common Knowledge)

Troyius developed into a major dilithium supplier for Starfleet and the Federation.

The peace between Troyius and Elas continued through the late 23rd and 24th centuries, with no significant violations of their treaty. However, renewed warfare remained a topic of great concern for the Federation, especially during the Federation-Cardassian War and the Dominion War, given the risk to Starfleet's dilithium supply. (Decipher RPG module: Worlds)

During the Borg Invasion of 2381, Troyius was threatened, but the SCE crew aboard the USS da Vinci succeeded in making the planet temporarily disappear, thus eluding attack. (Star Trek: Destiny novel: Lost Souls) Following the invasion, Troyius hosted numerous refugees and war survivors. In April and May of 2381, the A.C. Walden Medicine Show visited Troyius and played a number of concerts for the refugees there. (ST novel: A Singular Destiny)

Mirror universeEdit

In the mirror universe, Captain Spock of the ISS Enterprise was able to secure dilithium mining rights on both Troyius and Elas for himself, establishing himself in a position of significant power within the Terran Empire. (Star Trek: Mirror Universe novel: The Sorrows of Empire)


planets visited by the USS da Vinci
Magatha IVLamenda IVTenber VIIHofstrofSachem IIKalibissArtemis IXCallinon VIIDrovoer IIMariposaVemlarTellar PrimeMaeglinBetrisius IIILigon IIKharzh'ullaCoroticus IIIMerangueVrindaK'lnyGalvan VIKlorgat IVTroyius
planets visited by the USS Enterprise (NCC-1701) during Captain Kirk's initial five-year mission (2265-2270)
various Aprilia IIICaporyGarrus
2265 EarthDraxis IITallyAlpha Ortelina VIIArronus VIIAldebaran IIIM-155MestikoDimorusTendarArchernar IVDelta Vega IMiri's homeworldStarbase 127348-IIrobot planetTimshelK-GZartaMetamorphaNumero UnoMortiInicrustVoodoo planetGamma Alpha VStarbase 8 planetPollux IIDukarNeesanAlgenib II
2266 Beta IVRigel XIIPsi 2000Tlaoli IVAlpha Proxima IIAngiraBeta CarinaeExo III1324-IVCanaraNadorM-113Alfa 177Planet QBeneciaYkoTheta VII (Rell's world)Talos IVNumero UnoGateway
2267 Makus IIIBeta VIJanus VIOmicron Ceti IIIDenevaCeti Alpha VEminiar VIIBabelGamma Canaris 527Taurus IIHydra Epsilon IIIXimega IIPerseus Arm planetoidYkoSalvumGrotusRifas-LAmusement Park planetHeitius VIICentaurus VTyrtaeus IIGothosCestus IIINisusIron-silica planetZutotanium planetoidMuddEarthCanaraBeta IIIPyris VIIVulcanGamma XaridianPollux IVArgelius IIHalkaBavaryaNeolithiaMythraCapella IVGamma 400Magna RomaGamma Trianguli VISigma Iotia IIMasabaLekythosTyrtaeus IIShroud IVTycho IVDonico IIRimilliaOrgania
2268 Narnel's WorldNeuralAlpha Malurian VIBeta Canzadia IIIFornax IIGamma IITriskelionArgus XTycho IVTheta VIISigni BetaEarthPegasus IVCareta VDireidiEeiauoPatria IExo IIIT'nufoTranquility VIILeora IVAcademyDelta Canaris IVTautee star systemAmmdonMarcos XIIOctavius IVBeta CabriniAmerindBeta XII-AElasTroyiusSigma Draconis VIEkosScalosGideonBrellian IVPrastorDistrel
2269 MercanAnomalyEdenHolberg 917GSarpeidonExcalbiaAndrosPollux VAvalonCamus IIAragosTanisAleph PrimeKyrosBeta CastelliHeloxUnnamed Hoshan planetsChrellkan IIIChrellkan IVVidenDengella IIAlnath IISanctuaryMemory PrimeEphrata IVGelladorn/R-775 IVelat Nol/R-836 IITheta Tau VTalin IVAleph IIIBoaco VITrefolgMantillesMerak IIArdanaBabelOrganiaGatewayMaltos IV
2270 Isitra ZeroGatewayMercanDenebiaPhylos IIBeta Omicron Delta IIIMotherlodeMegas-TuTerratinSherman's PlanetArgoVedala asteroidDramia IIArretLactra VIIDelta Theta IIIArchernar IVCenotaphTaygeta VOkeanosElcidar Beta IIIYoondriAleriadAritaniYalboSycoraxTalos IVPillagra/R-855 IIIR-855EarthStarbase 12Tomarii

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