The 'unscrupulous inventions' of folk etymology

Rise, Sir Loin!

According to a 400-year-old story, the origin of the word sirloin goes back to a cut of beef knighted by an English king. Rise a knight, Sir Loin, be a good cut. I don't know what you think about the eccentricities of English monarchs, but dubbing a piece of meat might cut plausibility a bit too thinly.