The signing of the Treaty of Coruscant was a major event in the Star Wars universe taking place roughly three hundred years after the events of Knights of the Old Republic. It was an official armistice between the Republic and the Sith that ended formal conflict between the two parties. After being frustrated by Republic resistance to their invasion, the Sith made a calculated gamble by launching a massive blitz attack on Coruscant, the both the established center of galactic government and the home of the Jedi Temple. The defeat forced the Republic to sign a ceasefire, with terms generally favoring the Sith Empire.
The Treaty of Coruscant is the epoch of Star Wars: The Old Republic, with events being dated in terms of years before (BTC) or after (ATC) the signing of the pact. Although direct engagements between the Empire and the Republic are forbidden under the terms of the treaty, a hostile state still exists between the two similar to the Cold War between the United States and the Soviet Union. The result is an uneasy truce in which the Sith and Republic still clash indirectly with one another via espionage and the prosecution of proxy wars. Player characters in The Old Republic choose one of the two sides to fight with in this established cold war.