Very good quiz! Small things: allow "feudal" as well as feudalism? The clue about the UN really needs to say intergovernmental rather than government (which, to me at least, suggests one nation rather than lots of them).
The quiz description claims that all the answers except the quote are only one word. This is not the case. Names are usually alphabetized by last name, so Anne Frank should be an F, and Edward Jenner should be a J. This quiz needs serious reworking. Also, the letters should all reveal when the quote is guessed.