Nanclus

Nanclus was the Romulan Ambassador to the United Federation of Planets in 2293. That year, he was involved in an elaborate conspiracy to ignite a war between the Federation and the Klingon Empire following the explosion of Praxis through the assassinations of Federation President Ra-ghoratreii of Efros and Klingon Chancellor Gorkon, Son of Toq. While Gorkon was assassinated, Ra-ghoratreii was saved by Federation Starfleet Captain James T. Kirk and the conspiracy uncovered; Nanclus himself was arrested at the Khitomer Accords' opening ceremony. (Star Trek VI: The Undiscovered Country.)


 * Just why President Ra-ghoratreii allowed a representative of a hostile foreign government such as Nanclus to view the classified invasion plans for Operation: Retrieve is unknown.