Euhemerus (330-260 BC) was a Greek philosopher who gave his name to the method of rationalising myths as distortions of real history. Euhemerism particularly saw the ‘gods’ in Greek mythology as glorified manifestations of early kings and cultural heroes from a distant past. Support for this idea has waxed and waned over the centuries, with fewer followers today. An interesting paper^(a) by Professor William Harrison on this subject is worth reading.

^(a) http://community.middlebury.edu/~harris/GreekMyth/Preface.html