In April of 2281, a task force that included Diligence and the Belknap-class USS Haversham was ambushed by Orion pirates. The bridge of the Diligence was destroyed, killing Capt. Charles Austin and several division chiefs (Star Trek: Shadowstar Station: "The Honored Dead").
Many of the survivors from the Diligence were rotated to other assignments while the ship was in drydock.
Capt. Austin and the Diligence were derived from the author's and his brother's participation in the play-by-mail (PBM) RPG Starships of the Third Fleet around 1991.