USS Defiant (Enterprise class)

The USS Defiant II, NCC-1764, is referenced in a list of Constitution class vessels in the Star Fleet Technical Manual accidentally sent from one of many possible futures to the 20th century "Tomorrow Is Yesterday" universe, whence the Enterprise 1701 was accidentally propelled back in time in a freak mishap, causing the manual's contents to be accidentally downloaded into the main computers of the Omaha Air Force Station.

It currently seems odd that the second Constitution Class starship to bear the name would have the same registration number as its predecessor, that NCC-1764-A would be more likely, but possibly that traditioon did not exist at the time of the christening of the Defiant II. In fact, second ships to bear a name aren't typically called "II" either. Such are the mysteries of the multiverse.