Polytheism

The label polytheism is used where a plurality of gods are acknowledged and/or worshipped. Through the course of human history, polytheistic religions of one sort or another have been a dominant majority by far.

Polytheism is the belief that there is more than one god or goddess. This belief is held mostly by older religions, such as those of ancient Rome, Greece, and Egypt, and survives to modern times most notably in the Hindu and Shinto faiths, neopagan religions such as Wicca, Asatru, and Hellenism, and a range of indigenous religions in areas like Africa, the Americas, and Australia.

Roman "henotheism"
Contrary to popular opinion, Romans and Greeks of antiquity were not strict polytheists, but more comparable to "soft monotheists" with one divine presence and many smaller gods — in its own way, similar to Hinduism. As historian Gillian Clark writes in Christianity and Roman Society (2004):

The nature of polytheism
Polytheism typically involves many gods or gods/goddesses with different functions. There is division of labour among the gods/goddesses. Different gods have different functions and believers pray to the relevant god/goddess depending on what they want. The divine entities typically are seen as part of a divine community or pantheon and there may be a divine ruler who leads the other gods. Gods from other religions are treated in differing ways: Polytheistic religions are inherently flexible.
 * 1) They may be identified with an existing gods/goddess from the pantheon.
 * 2) They may be incorporated into the pantheon.
 * 3) They may be considered unworthy of worship.

Abrahamic religions
The Abrahamic religions developed largely amongst polytheistic religions (Canaanite, Roman, and Arab belief-systems preceding Judaism, Christianity, and Islam), and the initial ancestor of Judaism may have been polytheistic up until the Deutoronomic reforms under King Josiah. The early books of the Old Testament make a lot more sense if one imagines that the writers thought of YHWH as just one of many limited, rival gods - the Elohim. Some Christian denominations, most notably Roman Catholicism, preserve a memory of polytheism in the veneration of Mary and of other saints (many of whom some believers almost openly conflate with pre-Christian deities). Like polytheistic gods/goddesses, the various male and female saints have specific functions and Roman Catholics pray to a saint who deals with their particular issue. Syncretistic religions with Catholic roots such as Santeria, Vodoun, and Umbanda are essentially polytheistic religions (African-derived, in the case of the above three) combined with Christian names and worship-forms.

Real monotheists, such as Muslims, regard Trinitarian Christianity (seen as involving three gods), as hopelessly polytheistic.

Polytheism in literature
Numerous writers, many based on questionable historical research, others as part of a science fiction or fantasy storyline, have related the gods of ancient mythology to presumed-real alien life forms or paranormal beings. Such theories, for example, have informed the works of historian/huckster Erich von Däniken, and were the basis for the Star Trek episode Who Mourns for Adonais?, Philip K. Dick's 1954 short story, Strange Eden, and much of the storyline of Stargate.

Likewise, polytheism is the default position in fantasy role-playing games as Dungeons and Dragons even if in practice characters even outside classes as clerics and the like tipically follow just one deity as their patron(ness) while at least acknowledging others exist, and every god(dess) has his/her own self-contained church instead of one for all of them.