Arbitan (species)

The Arbitans were a humanoid species native to Marinus. (PROSE: The Fishmen of Kandalinga) They were pacifists until the Voords forced them to fight. They conquered the Voords by fixing the Conscience of Marinus. (TV: The Keys of Marinus)

When the First Doctor returned to Marinus he found that "with the passing of the centuries the whole race had assumed the name of their great dead leader" - Arbitan. (PROSE: The Fishmen of Kandalinga)