It's called reading a book and studying the lore.
My mistake, I play the game and study RL history. But I played enough to see what is going on in there. Several hundreds of hours. And I see the state of things.
I walked all the land. Not wanting to choose sides.
But with the time I feel the danger. The danger that guy represent for all. I went to his palace and listened to him. I was horrorized. I listened to his general... then I runned out directly to Solitude. That guy had to be stopped. His head must lie on a pick.