Just before the end of Empire the lead Battle AI programmer left CA to return to his family up north. Unfortunately, thanks to Mr Wilberforce’s efforts 200 years ago we couldn’t stop him. It left us with a battle AI, which at that stage, struggled to beat good players in a fair fight, and was pretty much at the mercy of great players, even with a level of handicap (I call it cheating) that is all too obvious.
More here:
http://blogs.sega.com/totalwar/2009/11/10/battle-ai-by-mike-simpson/