He wrote that "as 5 is to 8 so is 8 to 13, practically, and as 8 is to 13, so is 13 to 21 almost", and concluded that the limit approaches the golden ratio formula_26.
Prvi ga je dokazal Gottfried Wilhelm Leibniz v svojem rokopisu brez datuma, kjer je tudi zapisal, da je poznal dokaz že pred letom 1683.