After watching the most recent episode of QI, and being inspired by the discussion about Pierino da Vinci, I am now stricken with a plot idea wherein a cabal of history's most respected creators and geniuses go around travelling through time killing off the unsung proto-geniuses we've never heard of, before they can steal all the glory.

...yeah, I don't know either.

(Edit: Ooh, here's another contender: Thomas Linley the younger. Known as "the English Mozart", he actually wrote a concerto earlier than Mozart did - and then drowned at age 22 in a boating accident. Five bucks says envious little Wolfgang pushed him in.)