Well, you know how these things go. You start out defending your land, then you realise it'd be easier if you finished the mission that'll give you another foothold. Then you realise that the best way to defend your land is to take more, and more, and then you find yourself taking over France.Hmm, the sentence starts to sound interesting!
And lose its excitement right here :O
What disturbs me with that game is that the HRE doesn't have many troops...