Federation-Klingon War (2256-57)

The first Federation-Klingon War from 2256 to 2257, was fought between the United Federation of Planets and various Klingon Great Houses.

Chronology
The war was instigated by T'Kuvma in an attempt to unify the Klingon Great Houses against Federation expansionism. He orchestrated the arrival of Klingon and Federation ships at an Unnamed Binary Star System and fired on the Federation fleet. The was an early victory for the Klingons, despite the loss of T'Kuvma.

The Federation suffered early losses, including 8,186 in the first six months alone. Repeated attacks on installations such as Corvan II were slowly pushed back by covert use of Spore drive technology by the Federation. This technology was stolen from the USS Glenn and used, unsuccessfully, by J'Ula of House Mo'Kai resulting in her transport to the 25th century.

of House D'Ghor, having obtained T'Kuvma's cloaking technology, installed it throughout the Klingon fleet in exchange for their fealty. Following his death, the lose unity of Klingon houses under him fell apart. Despite their lack of coherent leadership, they maintained a strong and unyielding offensive against the Federation as they carved up Federation assets and territory between them; such as Starbase 1 falling to House D'Ghor and bearing the house's insignia, rather than that of the Empire.

An armistice was signed in 2257 following the accession, with the aid of the Federation, of Chancellor to the leadership of a unified Klingon Empire.