Star Trek: 12 Biggest Ever Retcons
7. A Conquered Vulcan?
The planet Vulcan is one of the most famous in Star Trek's history. It is the home of the Vulcan people, best known for the logical lifestyle they adopted to curtail the bloody violence that was a hallmark of their early history. Before becoming pacifists, Vulcans were such powerful warriors that in The Immunity Syndrome, Spock states that Vulcan has never been conquered. The idea of being conquered is completely foreign to them.
Vulcan warriors sound about as strong and terrifying as the Klingons based on that description, but in The Conscience Of The King, McCoy makes a wry observation of understanding why the Vulcans were conquered (being spared "the dubious benefits of alcohol"). This episode actually aired prior to The Immunity Syndrome, so the idea of Vulcan being completely unconquered was a new development.