A friend of mine stumbled on this gem and I have to say, as a fantasy writer, I totally slipped up on at least two of these. Looks like I had better buy The Time Traveler’s Guide to Medieval England: A Handbook for Visitors to the Fourteenth Century. More reading? Woe is me, what a terrible fate! Hehehe.
It seems a common thing to screw up on these ten details. Have a look-see! Perhaps you’re guilty too?