Leonhard Euler rescued from oblivion various arithmetic propositions of Pierre de Fermat. One notable case is the impossibility of the sum of two cubes being a cube. This is the particular case with the smallest exponent of Fermat's "Last Theorem," a famous result that remained a mere conjecture for three centuries.

Portrait of Leonhard Euler (1707–1783) by Joseph Friedrich August Darbes, 1778.

Euler's boldness ----------------
Euler's reasoning follows the method of "infinite descent" developed by Fermat: suppose there exist three nonzero integers x, y, z, such that *x 3 + y 3 = z 3.