Everyone knows that, despite its supposed nine lives, curiosity killed the cat. Well, not quite. The 'killed the cat' proverb originated as 'care killed the cat'. By 'care' the coiner of the expression meant 'worry/sorrow' rather than our more usual contemporary 'look after/provide for' meaning.
That form of the expression is first recorded in the English playwright Ben Jonson's play Every Man in His Humour, 1598:
"Helter skelter, hang sorrow, care'll kill a Cat, up-tails all, and a Louse for the Hangman."
http://www.phrases.org.uk/meanings/curiosity-k illed-the-cat.html
http://www.phrases.org.uk/bulletin_board/5/mes sages/291.html
The original (16th century?) phrase was "care kills the cat", no doubt referring to the independent streak that cats have, but that the proverb got altered over the ensuing years. I've also seen claims that the full version of the proverb is "curiosity killed the cat, and satisfaction brought it back".
http://www.phrases.org.uk/bulletin_board/17/me ssages/1083.html
The "Random House Dictionary of Popular Proverbs and Sayings" (1996) by Gregory Titelman states: "An overly inquisitive person is likely to get hurt. Children are usually warned against curiosity. The proverb was first attested in the United States in 1909. In 1921, it was used by (playwright) Eugene O'Neill.(A variation is) 'Curiosity killed the cat: satisfaction brought him back.'"