Unbeknownst the Terran colonists, the planet lay within Gorn space and was subsequently attacked and occupied by the reptilian race. The Imperial Starfleet launched a retaliatory raid on the planet which was interrupted by the arrival of advanced alien beings who referred to themselves the Metrons. The Metrons forced Captain James T. Kirk and his Gorn counterpart into a duel to the death. When Kirk hesitated to kill the Gorn, the Metrons took it to be a sign of mercy and weakness on the part of Terrans. Kirk and the Empire were then banished from Gorn space through the appearance of a vast energy barrier created by the Metrons. (Decipher RPG module: Through a Glass, Darkly)
The Terran Empire subsequently regained control of the planet and named its capital Kirk City in the captain's honor. (VOY - Mirror Universe novel: The Mirror-Scaled Serpent) However, the Gorn still maintained a presence on Cestus III. (TOS - Mirror Universe novel: The Sorrows of Empire)
In 2282, the Klingon general Kor met with a Ferengi black marketeer named Lorp on Cestus III to order to obtain information regarding a top secret project being run by the Imperial Starfleet aboard the supposedly abandoned Regula I Space Laboratory at the edge of the Mutara Nebula. Lorp's payment was a complete set of holographic schematics for a cloaking device. However, after reviewing the data, Kor's guards Gejh and K'mdek killed Lorp and his two henchmen using their disruptors. (TOS - Mirror Universe novel: The Sorrows of Empire)
Following the conquest of the Republic by the Klingon-Cardassian Alliance in 2295, the name of Kirk City was changed to Gorkon City, taking its name from Gorkon, the then Regent of the Klingon Empire.
Prior to 2371, B'Elanna served as the Intendant of Cestus III. However, she was overthrown by a group of rebellious Terran slaves who destroyed the administration building in Gorkon City and attempted to assassinate her before escaping the planet. Among the escaped slaves were Harry Kim and Kate Janeway, who was in actuality B'Elanna's longtime personal aide. Janeway was able to insinuate herself into the group but could not stop them from launching their attack on B'Elanna. (VOY - Mirror Universe novel: The Mirror-Scaled Serpent)