Henotheism has been around for probably as long as there has been polytheism- The Greeks, Romans, Egyptians, Atec, Incans, and Mayans at least seemed to practice some form of
…it, in that a deity was singled out of the pantheon and worshiped at a specific location, usually a temple or alter attended to by a dedicated priesthood whose sole job was to appease that particular deity throughout the year by means of rites, rituals, tithes and other sacrifices. ( Full Answer )