You might be interested in threads from the FAQ section on "How historically accurate is Game of Thrones / A Song of Ice and Fire?":

##General Comparisons

-o- What common medieval fantasy tropes have little-to-no basis in real medieval European history? - 263 comments, over 10 months old.

• There is an exhaustive list of questions posed by the original poster which is met by an equally exhaustive list of answers by a flaired commenter with many followup questions and comments branching off from it.

-o- Were the Middle Ages anywhere near as violent as the TV show 'Game of Thrones'? - 166 comments, over 10 months old.

• Flaired commenters here get into an extensive debate on which historical time period and place Game of Thrones is most accurately compared with and if it should be compared in such a manner owing to the show setting's unique geographical concerns and fantasy elements.

-o- How believable are the setting and events in A Song of Ice and Fire? - 36 comments, over 2 years old.

• Commenters here make some comparisons from specific time periods and events in the Middle Ages and the books and show in question, as well as debate the merits of the "feudal" system in a landmass the size of Westeros.

-o- What aspects of life in middle ages Europe do movies always get wrong? - 499 comments, less than 1 month old.

• The OP actually references Game of Thrones in the post text, and the commenters go on to discuss differences in lighting, medicine, and accents from what is found in Medieval Fantasy works.

-o- What wrong ideas about medieval Europe might one get from popular works of "medieval fantasy"? - 513 comments, over 1 year old.

• Commenters here discuss in detail common errors in cuisine, body size, lighting, combat, medicine, and other issues.

-o- Where do we get our idea of this medieval fantasy setting?(first time poster) - 29 comments, over 1 year old.

• This thread goes into the origins of Medievalism in the Victorian Era and how it shaped modern representations of the Middle Ages.

What time period and/or place does Game of Thrones / A Song of Ice and Fire most resemble or borrow the most inspiration from?

-o- Given the technology, political institutions, and social structures in the Game of Thrones series, which century does it most closely resemble? - 96 comments, over 1 year old.

• This thread picks apart individual elements from the types of armor used by the knights to the political situation at large and associates each of them with the most appropriate time period.

-o- What historical connections are there between Game of Thrones and War of the Roses? - 36 comments, over 1 year old.

• Users here pull out a variety of names (many with Wikipedia links), places, and events from the historical War of the Roses and their analogues in Game of Thrones / A Song of Ice and Fire.

-o- What area of history would you recommend to a fan of A Song of Ice and Fire? - 10 comments, over 2 years old.

• Commenters here pull out specific periods and places from Ancient and Medieval Europe as well as one from China.

-o- Does A Song of Ice and Fire (Game of Thrones) base it's story on any historical events? - 12 comments, over 1 year old.

• This thread associates many events and groups in the show and books with their possible historical inspirations but does not lead to any major analysis of either the history or the fantasy.