Unlike modern monotheistic religions that only accept one, omnipotent and omniscient god, ancient Greek religion has a pantheon of fallible gods. Yet it was also well developed, where the pantheon has hierarchy (Zeus, king of gods) and lineage.
Was there ever a time and place where the religion evolved into a monotheistic form? That is, only accepting one god, rejecting the others as false ones or manifestations of the one true god. For example, ancient Egyptian religion briefly gave rise to Atenism, the offshoot religion that states the sun-disc Aten was the only god.
Did a similar thing happen to Greek religion? If so, which god became the one? Or was it an amalgam?