The Dominion War was a major interstellar conflict, fighting from 2373 to 2375, although related conflicts began earlier. The war affected all the major powers of the Alpha and Gamma quadrants, which were organized into two opposing military alliances: the Federation Alliance and the Breen-Dominion Alliance. Marked by massive military and civilian casualties, including the systematic destruction of the Cardassian population (killing more than eight hundred million Cardassians) and the massive mobilization of starship fleets, it was one of the bloodiest and most destructive wars in modern galactic history.