Humanoids of Troyius in the Tellun system, long at war with neighbouring Elas until a royal marriage was arranged to secure peace.
The Troyians are a humanoid people from Troyius, a planet in the Tellun star system that fought a long war with the neighbouring world of Elas. Troyians see themselves as cultured and refined, and they regard the Elasians as fierce and uncivilized.
In Elaan of Troyius, the Enterprise carried Elaan, the Dohlman of Elas, to Troyius for a marriage intended to end the conflict, while the Troyian ambassador Petri tried and largely failed to teach her Troyian manners. The Klingons worked to sabotage the arrangement because the Tellun system was a source of dilithium.