What do we mean when we say it today?
We've all heard "off with his head" today, too. The phrase was used in Alice's Adventures in Wonderland. Leave it to the Queen of Hearts to copy Margaret. We see a lot of similarities between those two divas.
Ever since then, it's been pretty popular in movies and on TV. But we've only ever heard this phrase in a joking sense in real life. We're pretty sure that's the case for you, too. No one actually orders someone else to chop off someone's head in a literal sense. If they do, you should de-friend them on Facebook immediately.