As part of the Shakespeare season on BBC, costume designer Eliza Kessler sat down to answer some questions about historical period drama. Kessler explains she immersed herself in paintings, visited buildings, and even studied modern football games to get an idea of 'chivalry'; all to immerse herself in the c.15/16th centuries. Kessler describes that the costumes must not only to look real, but to be versatile so the actors can move around and, to use her phrase, look "sexy." (she's talking about tom hiddleston here i believe.) It's a really interesting interview as it sheds some light on a topic that should get more attention.
Also, I would blatantly fight for tom hiddleston if he gave this speech...just saying.