The Valiant was a Galactic Republic starship during the First Jedi Purge. In 3951 BBY it was captained by Opelle.
Behind the scenes
The Valiant and its captain were part of a subplot in the video game Star Wars: Knights of the Old Republic II: The Sith Lords involving the hostile takeover of Citadel Station by Czerka Corporation that was ultimately cut from the game. However, a droid at the Telos Security Force offices refers to Admiral Carth Onasi's ship as the Valiant in conversation (in contrast with the subtitles and the rest of the game, which call it the Sojourn).