It was long ago that poly­the­ism, as the sto­ry comes down to us, gave way to monothe­ism. Human­i­ty used to have many gods, and now almost every reli­gious believ­er acknowl­edges just one - though which god, exact­ly, does vary. Some pop­u­lar the­o­ries of "big his­to­ry" hold that, as the scale of a soci­ety grows larg­er, the num­ber of deities pro­posed by its faiths gets small­er.