Troyius
Troyius is the outer planet of the Tellun Star System located 0.037 light years from the system's inner planet, Elas. Troyius is the home world of the Troyians and is governed by the Troyius Tribunal. On Troyius, radans, which are better known to the Federation and Klingon Empire as dilithium crystals, are rare.
Troyius and its neighboring planet, Elas, had been at war for many centuries. Peace was finally established in 2268, as the ruler of Troyius was to marry Elaan, Dohlman of Elas, as the final gesture of peace between the two planets. (TOS: "Elaan of Troyius")