I wonder whether the Kzinti might be mentioned? There inclusion into Trek lore seems a tricky issue.
They and Earth were in conflict some "200 years" before 2269 (TAS: The Slaver Weapon
That would only happen with Larry Niven's blessing, and I'm not sure he'd be inclined to grant it, particularly since there's been a spate of new Known Space novels over the past few years co-written by Niven and Edward Lerner, the Fleet of Worlds
series, so it's a going concern again. I tend to feel that Trek and Known Space should remain their own distinct universes anyway.
Despite that preference, I have actually given some thought to whether TSW's backstory could somehow be tweaked in a way compatible with currently known Trek history, and I just couldn't see it. We know from "Terra Nova" that Earth's first interstellar colony was founded in 2078 and failed five years later, and we don't know how much later it was that Alpha Centauri, Vega, and other worlds were colonized. But it does seem that Earth expanded rather slowly in those early decades, and that the Vulcans were overseeing them rather closely, and probably protecting them from potential threats. The Earth we saw at the start of ENT was quite naive about interstellar contacts, probably because of Vulcan sheltering; Archer and his crew didn't know much about other races and didn't expect they'd run into many hostile aliens. If they'd been through a series of wars against a vicious race of spacegoing tigers in the previous century, they wouldn't have had such rosy expectations.
Yes both the United Earth Foreign ministry and the Starfleet Intelligence were not doing their job yet. Perhaps this is why Section 31 had to go into the high gear in the 2150s.
As to the peaceful nature of humans. We know that it took till 2130s that United Earth was formed, by the 2070s the people were still barbaric. So I don't see humans defending themselves against 4 fleets (= 4 "wars") in the very early decades of the 22nd century that implausible, after all it would be several generations before the unification is done and humans become such as we see them.
On the other hand there was an untold number of unsanctioned colonies (Moab comes to mind but there were surly others more in line with this premise) to the known (Terra Nova, AC, Deneva ...) and/or transplanted humans. So is it not likely that the Kzinti were feuding with these? Although than the Sirius in the Treaty of Sirius has to have an other meaning than the star.
Steve Mollmann wrote:
Hm, wasn't the Federation war with the M'dok (the thinly veiled Kzinti substitute in The Captains' Honor) in the 22nd century?
Also, the war with the Tarn (from The Forgotten War) was either in the 22nd century or the 23rd, depending on which dating cues you believe.
The character ages make only the 23rd century believable. the 22nd century is too early and a war this early in the Federation history would have shaped the society in a wrong way.