Fermat lived into his 60s and died of natural causes AFAIK, wrote in the margins he didn't write down the marvelous proof for lack of space. Galois died in a d

Fermat lived into his 60s and died of natural causes AFAIK, wrote in the margins he didn't write down the marvelous proof for lack of space. Galois died in a duel at 20, writing down his mathematical testament the night before he died and scribbling in the margins 'I have no time'.