Makes sense both in the original context and in the later one. Earth's dominion wasn't that big in the "ancient" times a century before the TOS episode - by implication and writer intent as regards TOS, by explicit storytelling as regards ENT. Any enemies they made back then would be close neighbors, and if the enemies weren't turned into allies, they'd become encapsulated dangerously close to the ever-softer heartlands of the UFP as the tough frontier moved outward.
Klingons aren't explicitly "ancient" enemies in TOS in this sense, but they become such in later stories. TOS movies still speak of just seventy years of open animosity in the 23rd century, but TNG episodes speak of "first contact centuries ago" and the like. Heck, it's quite difficult to establish any of the adversaries as not being ancient... Thankfully, at least the Cardassians were immediately associated with mid-24th century "border wars" rather than ancient core scuffles!
Timo Saloniemi
Klingons aren't explicitly "ancient" enemies in TOS in this sense, but they become such in later stories. TOS movies still speak of just seventy years of open animosity in the 23rd century, but TNG episodes speak of "first contact centuries ago" and the like. Heck, it's quite difficult to establish any of the adversaries as not being ancient... Thankfully, at least the Cardassians were immediately associated with mid-24th century "border wars" rather than ancient core scuffles!
Timo Saloniemi
