What determines battle order?

[littlemute]

that makes sense except for one instance.

Say I move and army to a province where an enemy army resides and during the same turn he moves to the province my army resides in. From what you mentioned, my army would fight him off in my province if he once owned it, but what happens if the province only has one owner.

I was wonderng because I had a large army at an enemy's fort and I tried to move it away for a couple of turns, but it was always stopped by a smaller force that attacked to province. Even though I won the battle, I couldn't move my army.

I though this was strange.