In 2371, a Founder posing as a Federation ambassador attempted to start a war between the Federation and the Tzenkethi by convincing the USS Defiant to set a course for Tzenketh, telling the crew that the Autarch had been overthrown. The crew were able to regain control of the Defiant before it attacked the Tzenkethi. (DS9episode: "The Adversary")
In 2410, the Autarch had begun development of Protomatter weapons and begun using them to wipe out life on various planets in the Alpha quadrant. While seemingly random at first, it was later discovered that these strikes were intended to wipe out incubating populations of Drantzuli on the targeted worlds.