In this similarly titled thread
, there is a discussion about how various mentions in TOS' run strongly suggest the show was set in the 22nd century, less than 200 years from today. (Possibly just over 150 years from today.)
That having been said, what are the earliest references in TOS canon that suggest TOS was actually in the 23rd century, and what specific references was focus on the shows being set about 300 after their production dates? (1966 -> 2266?)
Off the top of my head, I can think of the first two movies, THE MOTION PICTURE and THE WRATH OF KHAN, as anchoring TOS in the 23rd century. Are there any other references in TOS or TAS that at least suggested this?