The Federation-Klingon War of 2267 was a brief conflict fought between the United Federation of Planets and the Klingon Empire in 2267. It was the result of years of tense build-up in a cold war situation, but was ultimately inconclusive because the fighting was abruptly ended by the Organians. (TOS: "Errand of Mercy" ) Ayelborne also predicted that the Klingons and the Federation would one day become fast friends – a prospect scoffed at by Kirk and Kor, but one that ultimately proved true. (TOS: "Errand of Mercy" ; Star Trek VI: The Undiscovered Country)