Some theists believe in more than one god. I wonder if a polytheist in anciant Greece which believed in one less god (e.g. didn't belive in Cronos, but did bel

Some theists believe in more than one god. I wonder if a polytheist in anciant Greece which believed in one less god (e.g. didn't belive in Cronos, but did believe in the rest of the pantheon) would be concidered an atheist by his contemporaries?