2168

Events

Briam of Krios Prime is born. (TNG: "The Perfect Mate")
The starship Horizon visits Sigma Iotia II, a planet that is home to the pre-warp Iotians. One of the starship's crew members accidentally leaves behind a book, Chicago Mobs of the Twenties. The Horizon is lost shortly after leaving the planet, but transmits a radio frequency distress call that is not received by Starfleet until almost a hundred years later. (TOS: "A Piece of the Action")

"A Piece of the Action" implies that the Prime Directive was not in force at this time.