http://online.wsj.com/article/
I really appreciate the effort some authors expend to get the details right. Historical fiction has a lot in common with science fiction, where the technology ought to be theoretically plausible, and fantasy, where the imagined world ought to be internally consistent and realistic within its constraints -- which is why we have people like Asimov writing science fiction, people like Tolkien writing fantasy, and a bevy of actual historians writing historical fiction. It's hard to do these genres well if you don't have the background.
I have made my own period costumes, and sporadically partake in historical reenactment (and yes, I do own a corset). I do my research; Stanford's libraries are excellent for this purpose. And as I sometimes mention on this blog, I'm a history major -- but I'm still, compared to film industry costumers, an amateur. Inaccuracies in books, films, etc. bother me quite a bit, because I always find myself thinking, if I, as a hobbyist with limited resources, can get it right (or at least moreso than this film), why can't a professional crew? (Some of my friends apparently enjoy watching bad quasi-medieval action flicks with me just to watch me go off about all the things the studio got wrong. Not sure what that says about me -- or them, for that matter.)
Anyhow. A pet peeve of mine.