- Doctor Tristan Adams begins to revolutionize and humanize prisons and the treatment of prisoners by developing new methods to treat the criminally insane. Meanwhile, the Federation begins to convert a number of their penal colonies over to asylums to treat inmates, rather than to "cage" them up. (TOS: "Dagger of the Mind")
- An exotic fungus destroys most of planet Tarsus IV's food supply. (TOS: "The Conscience of the King")
- James T. Kirk – at the age of thirteen – is one of nine surviving eyewitnesses to a massacre of some 4,000 colonists on Tarsus IV by Governor Kodos. After Earth Forces finds a burned body that is assumed to be Kodos, the case is closed. Still alive, Kodos secretly assumes the identity of actor Anton Karidian. (TOS: "The Conscience of the King")
- Unused material for Hoshi Sato's bio seen in ENT: "In a Mirror, Darkly, Part II" stated that she and her family were among the victims at Tarsus IV.
- It is possible that the events on Tarsus IV started on stardate 2794.7. In the episode, the computer states, "Working. Kodos the Executioner, summary. Governor of Tarsus Four, twenty Earth years ago. Invoked martial law. Slaughtered fifty percent of population Earth colony, that planet. Burned body found when Earth forces arrived. No positive identification. Case closed. Detailed information follows. On stardate 2794.7..."