From the very beginning of this novel, I was thrown off. Although this is set in the 15th century, the very first sentence threw me out of the book:
“The hammering on the door shot him into wakefulness like a handgun going off in his face.”
I had to put the novel down and go to Wikipedia, determined to find out the truth of the matter and grow about my own superior knowledge. I skimmed some of the entry and then happened upon this small paragraph in the handguns entry:
Handheld firearms first appeared in China where gunpowder was first developed. They were hand cannons (although they were not necessarily fired from the hand, but rather at the end of a handle). By the 14th century, they existed in Europe as well.
You win this round, Philippa Gregory.