The Klingon-Cardassian War was a conflict between the Klingon Empire and the Cardassian Union that took place from 2372 to 2373. The war was precipitated by the Klingon belief that the Cardassian Union had been infiltrated by changelings, but in fact it was the Empire that had been infiltrated, as General Martok had been replaced by a changeling. The war resulted in the devastation of the Cardassian Union, which paved the way for the Dominion to take control of the Union later in 2373. (DS9: "The Way of the Warrior", "By Inferno's Light")