Travell was a staunch defender of the Tollan's highest law: they do not share their technology with less advanced species. She was known to administrate triads (as a judge), as well as negotiations with other worlds, such as Earth.
When Anubis's forces bore down upon Tollana (commanded by Tanith, who came in a ship with new shields impervious to the Tollan defensive weapons network), Travell and the Curia were forced to strike a deal with the Goa'uld. In exchange for the survival of the Tollan people, they would create advanced weapons of mass destruction, capable of bypassing even the iris protecting Earth's Stargate.
But SG-1 and the Tollan Narim, learned of Travell's plans. For the sake of Earth and the rest of the galaxy, Narim used the Tollan ion cannons to destroy the manufacturing facility. Tanith attacked, placing Travell and the rest of her people in the midst of a war they could not win. Travell and the Tollan are presumed dead.
Pretense - Travell officiates the dispute between Skaara and his Goa'uld symbiote for control of his body. But when SG-1 investigates a Goa'uld plot to attack Tollana, Travell arrogantly thwarts their attempts to protect her world.
Shades of Grey - Travell refuses SG-1's request that the Tollan share technology, but demands that the S.G.C. apprehend a group of rogue N.I.D. operatives who have been stealing their technology.
Between Two Fires - SG-1 is shocked when Travell offers to share Tollan weapons technology with Earth, but learns that she and the Curia have struck a deal with the Goa'uld to produce weapons of mass destruction for them, in order to save their own planet from destruction.