After what has beeen said, I guess that the game does all movements pseudo-simultaneously within each of the categories:
- magical movement
- friendly movement
- hostile movement
After
all moves in
a Category are done, opposing sides located in the same province result in a battle (more or less random order if more than two opposing sides are there).
The lone exception would then be (hostile) movement from A->B and B->A, where a chance for meeting exists...
This sounds quite plausible to me as well, as logging previous owners and hideously calculating the worst outcome for everyone seems difficult to implement to me (but I am only a theoretical computer scientist from university and not a bastard programmer from hell, so I might well be wrong on programming issues... 
)
...so nevertheless
if the principle stated above is true, one might have an alternative to stop a raiding army:
Say a raider is in province A and will move to and attack our lovely proince B. But this is unknown to us, the good guy, since there are plenty of lovely provinces adjacent to A. But we managed to sourround the foul raider in province A by our scouts, all set to move-attack province A and our big huge army, located in C, also attacks province A.
Now that scout which was located in B, the enemies infernally selected secret target, meets the raider on the borderline, steps out of the woods and stops the heathens! (i.e. we got lucky and the armies met.) Now (again by random chance) the fight may take place either in B (killing the lone ranger), or it could happen in province A.
The question is: Would our huge army from C be already present to help our brave scout coming from B fighting in A?
According to what I've said it would be so. This is also in accordance with the observation that all friendly troops
always fight together in once province. I've got to test this...stay tuned!!!
[Edit: clarified some parts]
[ June 08, 2004, 13:58: Message edited by: Chazar ]