A war that was fought between the Federation and the Tzenkethi Coalition, triggered in 2353 and lasting for eight years. For decades prior, the UFP attempted to establish both diplomatic and economic ties with the Tzenkethi. Eventually some trade was established, with Federation ships given limited access to the fringes of Tzenkethi space. This changed in 2353, when U.S.S. Rickover penetrated deeply into Tzenkethi territory without realizing what they were doing. The Tzenkethi overreacted to this seeming invasion of their territory, striking at the Rickover with three escort vessels, in an effort to drive it from their territory. The Rickover responded in kind, withdrawing but destroying two of the escorts. The Tzenkethi immediately massed vessels and followed, attacking Federation starbases and starships in retaliation. The resulting war was centralized along the border areas, and punctuated by vicious ship-to-ship encounters.
The U.S.S. Okinawa—commanded by Captain Robert Leyton, with a young Benjamin Sisko in his first command position in Starfleet as his first officer - was instrumental in resolving the conflict and negotiating the Federation-Tzenkethi ceasefire. (DS9: "The Adversary")