"This ally has attacked your army....

[Weebeast]

and is now your enemy!"

I found the above message in changes.txt so it's possible for you to get attacked by your ally[ies] in battle field. Have you had your ally turning on you on the battle field? Although there's an entry in the loc file, this kinda stuff rarely happens in campaign. I actually have not experienced something like that.

Now I figure this does/can happen on mp battles but regardless, CA should tweak this for sp campaign, don't you think? Say if your king isn't that influential, your army is outnumbered by your ally, or that disputed province belongs to your ally in the period, then should alignment switch happen.

[Knight Templar]

Yes, it's possible, although I never had that experience. If you drag the cursor (during the battle) on your ally's army, sword will (like it's your enemy) appear. If you click on it game will ask you if you want to attack your ally. If you click yes, they'll become enemy of yours.
So if youu can attack your allies during the battle, I suppose they can aslo attack you.

[Roark]

As the Scottish, I was stabbed in the back by my Pictish allies, facing the Northumbrians.

I slightly outnumbered the Picts and so, after the battle, the province would hypothetically have gone to me. King Brun the Extremely Hairy would have nothing to do with it, though, and sent 3 units of Berserkers into the rear of my army as things were winding down. I was dominated in a bad way....

[ajaxfetish]

Wow, that's cool. I've seen the option to attack my own allies in the field, but never have gone with it (battles with the help of an ally are rare enough anyway that I appreciate them too much to do the backstabbing). I've never seen an ally attack me and didn't imagine it would actually ever happen. Thanks for sharing.

Ajax

[m52nickerson]

I had a battle were the HRE and my self (Poland) attack the same Hungarian provence as allies. As the Huns were routing off the field the HRE attacked my lines. Luckily I was able to hold them off long enough to have my cav flank them. I won in the end but took heavy loses. Of course I then made peace with the Huns a few turns later as I was kicking the hell out of the germans.

[Weebeast]

Well this is easy to trigger after all then. I mean two people in this thread have had that experience. It's just that I don't know how or it's pretty random lol.

Cool..cool...