A reply to Olbers' attempt in 1816 to entice him to work on Fermat's Theorem. I confess that Fermat's Theorem as an isolated proposition has very little interest for me, because I could easily lay down a multitude of such propositions, which one could neither prove nor dispose of. 
Source: J. R. Newman (ed.) The World of Mathematics, New York: Simon and Schuster, 1956. p. 312.
Contributed by: Zaady