The Racnoss Wars were a conflict between the Time Lords' Fledgling Empires and the Empire of the Racnoss. The Fifth Doctor described the Racnoss Wars as "a long and bloody affair". (AUDIO: Empire of the Racnoss) It was one of several wars which the Time Lords fought and won in the Time Wars period. (PROSE: River of Time)
The Racnoss attacked a Fledgling Empire outpost on Trakkiney during the wars. (PROSE: The Labyrinthine Web)
The Fifth Doctor's TARDIS was brought into the conflict after a conscientious objector circuit was activated. (AUDIO: Empire of the Racnoss)
Almost all of the Racnoss were wiped out in the conflict, apart from one Webstar, the Secret Heart which escaped to the site where Earth would be formed. (TV: The Runaway Bride) Rassilon boasted to Pandoric that he had "wiped out the voracious Racnoss." (PROSE: Pandoric's Box)