TstclrCncr:

If we stop guessing and start stating facts we could narrow down the possibilities. 

So true.

wyattFNearpp:

Just because they use the word 'war' doesn't mean there weren't battles before this instance.  There may have been skirmishes or encounters that were violent. 

 Sorry about this contradiction wyattFNearpp: this Halo Wars game (hopefully everybody now knows) is said to be set before the game Halo: Combat Evolved. The reasons for the Spartans could well be that they part of the SPARTAN-1 project. MC and the rest were part of the SPARTAN-2 project. Also the reason for this is that when the the leader of these Spartans says "if they want a war we'll give 'em one", this I think shows that it is definitely nearer the beginning of the Human-Covenant encounters. In the first book Halo: The Fall of Reach, i think the first encounter of the Covenant is when the Spartan-2s are being trained in some underground cavern on Reach?

However, when some of the Spartan-2s fought against the Covenant on Sigma Octanus 4, in Cote d'Azur, there were only 12 of them. There were still 20 other Spartan-2s not there, so they could have been transferred to fight the Covenant on other planets which have been un-named. These facts and theories may help provide you with enough information to think of others, or whatever. I just hope it helped narrow down the possibilities.

:p Tuek