From The Old Republic Wiki

The Great Hyperspace War was a war fought between the Galactic Republic and the Sith Empire in 1347 BTC (5000 BBY).

The conflict encompassed the entire Galactic Republic, though the main forces focused their attention on three Republic worlds, and later took the war to the remote star system Primus Goluud, and the Sith mausoleum world of Korriban.

After it overcame the initial shock of the Sith invasion, the Republic's armadas regrouped and annihilated the Sith Empire, forcing the Dark Lord Naga Sadow to exile himself to Yavin 4.