At turn one you must choose one of three ways for Rohan. It can work to blitz Isengard in the beginning of your campaign, but remember that you must NOT only have your armies consist of cavalry only. This very reason is caused by too much focus on war and creating huge armies. If you have ever played Rohan, you must know that you will sometimes have your economy drop drastically. They are the generals you will be using most of the time because of their ability to win nearly all battles. You start with several generals, including both King Thengel and Lord Theoden. It is a mighty realm with several strong cities, the most powerful of them all Helms Deep and Edoras. What you see infront of you now, is your kingdom.