Quote Originally Posted by ReluctantSamurai View Post
Bear in mind that I play a modded version of vanilla RTW and I haven't bothered with any TW games since M2TW. Later games might have implemented this feature...I wouldn't know of it then.

But in vanilla RTW, an army can decide to fight or retreat irregardless of the mobility factor. I play mostly the Armenia faction and by mid-game I have several all cataphract armies roaming the country-side and I can tell you that an all infantry army very often retreats from my initial attack requiring me to attack them a second time....that's just not right considering that infantry could hardly escape from cavalry except, perhaps, in a heavily wooded situation.
It's still like that. You can explain the current behaviour by saying that the army icon only represents an army dispersed in a general area that has a certain amount of strategic mobility (+baggage trains, etc.), but the way it's represented makes it look like the whole army is in one place.