The Battle of Toprawa was fought during the Great Sith War.
The date of Barrison Draay's death is given indirectly in Star Wars Knights of the Old Republic #9; It can be calculated via simple math applied to numbers provided in the issue: 3,963 (The events of this story take place approximately 3,963 BBY) + 30 (Coruscant, the Draay estate. Thirty years ago) + 4 (It's been four years since your loss)=3,997 BBY.
However, in issue #33, Dossa tells Haazen that "Exar Kun's pulling back, maybe to Yavin," a statement that would make more sense if the battle took place in 3,996 BBY.
When asked about the dating discrepancy, John Jackson Miller said that "Toprawa is one of the later acts in the war, but it could still be in 3997."
- The Essential Atlas