This video should help you understand the events of GOT in better context as it details historic events not featured in the show.
Additionally this video acts as a refresher course for GOT viewers to get primed for season Three. This video also features some information from the book that is not included in the show.
Warning: Video contains strong language.
Warning #2: This video contains severe spoilers for those who have not yet seen season 1-2 of Game of Thrones.