From: Star Trek: The Original Series
Planet: Elas. A fierce humanoid warrior culture at war for years with the neighboring planet of Troyius until both cultures achieved the technology necessary to wipe both themselves and their opponents out. On stardate 4372.5, the U.S.S. Enterprise NCC-1701, under the command of James Kirk, is ordered to act as a neutral courier for the Dolman, Elaan to deliver her to the leader of Troyius in the hopes that their marriage would bring peace to their two worlds.