Klingon Empire

The Klingon Empire is an interstellar political entity, headed by the Klingon Chancellor and High Council, based in the Great Hall in the First City on planet Qo'noS.

The empire was begun by Kahless the Unforgettable, who first united the Klingon people. Fifteen hundred years later, a clone of Kahless was installed as emperor, the first in three centuries, though given no political power. (TNG episode: Rightful Heir)

Non-Klingon subjects of the Klingon Empire are called "jeghpu'wI", a status greater than slave, but less than citizen. (TNG novel: Diplomatic Implausibility)