Terran Republic
From Star Trek : Freedom's Wiki
In the Mirror Universe the Terran Republic was the ruling entity of a sector of space that was previously governed by the Terran Empire It was established by Regent Spock in 2293.
It was meant to be a more benevolent political entity than it's predecessor. Spock however, failed to foresee the power vacuum that the dissolution of the Terran Empire would entail.
In just a little under two years, the Republic would be no more. The Assassination of Spock and Moreau and the subsequent invasion of the Republic by the Klingon-Cardassian Alliance in 2295 would seal it's fate.