The mythology of the Stargate franchise is a complex and eclectic fictional backstory, which is presented as being historical, of the Stargate premise. A "rich mythology and world-building" are used to establish "a vast cosmology and an interesting alternate take on the history of Earth"; a defining feature is "its use of ancient mythology, with stories that take inspiration from multiple places around the globe". Narratives center around xeno-mythology as experienced by humans during episodic contact with alien races. Audiences across a variety of platforms - including TV series, novels, comics and movies - witness the people of Earth exploring a fictional universe using the Stargate. Species established early on in the franchise recur throughout, with one adversary often dominating a particular story arc, which can continue across several seasons.

In addition to a diversity of alien life, the Stargate universe includes an abundance of humans who, prior to the events depicted in the various Stargate fictional vehicles, have been scattered across the cosmos by advanced aliens. Some of the most significant species or beings in Stargate SG-1 are the Goa'uld, the Asgard, and the Replicators. Stargate Atlantis, set in the Pegasus Dwarf Irregular Galaxy, introduced the Wraith and the Asurans. One of the most influential species in Stargate, the Ancients, are revealed to have moved on to a higher plane of existence. "There's no shortage of familiar myths to be found in the Stargate franchise, even if they are transformed to fit sci-fi parameters."

Frederic Krueger notes the re-emergence of the Ancient Astronaut Discourse (AAD) in the 1990s, and points to "the continuous mutual influence between the AAD and popular culture, exemplified via the rather spectacular case of Stargate". For example, an origin theory for human populations shown to inhabit the Milky Way galaxy in Stargate SG-1 holds that the Goa'uld transplanted humans from Earth to other planets for slave labor. Many of these populations were abandoned, often when deposits of the fictional precious mineral naquadah were exhausted, and subsequently developed their own unique societies.

Some of these extraterrestrial human civilizations are shown to have become much more technologically advanced than those on Earth, the in-show rationale being that they never suffered the setback of the Dark Ages. The most advanced of these humans were the Tollan, who were destroyed by the Goa'uld in Season 5's Between Two Fires. Another example of AAD in the mythos is the creation of human populations in the Pegasus galaxy by the Ancients, few of which are technologically advanced, as the Wraith destroy any civilization that could potentially pose a threat. Audiences are also made aware of large numbers of humans in the Ori galaxy, where human worship enhances the power of the Ori.

Eclectic borrowings

Scholars have remarked on the multiple borrowings of real-world mythology to provide Stargate settings. Mariella Scerri and David Zammit note numerous such uses in Stargate.

+ Examples from Mariella Scerri and David Zammit's analysis of mythological figures in Stargate Real world mythology Figure Stargate Ancient Egyptian "a key aspect of its appeal" Aztec Cōātlīcue "remarkably convenient resemblance" to Goa'uld queen Hathor Biblical mentioned in Exogenesis Ancient Greek Atlas, king of Atlantis Moros, leader of Atlantis; possible grudge with Atlas Sumerian epic Gilgamesh Ea, "god of primordial waters" "terraforming engineer" aka creation god, avoiding"potentially delicate marketing issue of using the Judeo-Christian God"

Frederic Krueger analyses the use of Ancient Egyptian mythology, and concludes: "From a critical standpoint, Stargate gives the initial impression of a very confused pop-cultural salad, randomly tossed together out of the vegetable bins of sci-fi, American military triumphalism, and a lot of Orientalizing Egyptomania. Yet the film was a lasting hit". Ultimately, he concludes that Stargate "serves as a neo-mythology able to re-enchant the world, to present an attractive anti-authoritarian option for identity formation and yet functionally equivalent to religion (according to traditional modern definitions) in its creationist tenet".

+ Examples from Frederic Krueger's analysis of Ancient Egyptian elements in Stargate Ancient Egyptian element Stargate Abydos, a city Abydos, a desert planet Temples, pyramids Similar artefacts; planet is populated by descendants of enslaved Ancient Egyptians Ra, god of the sun Tyrant has "assumed the persona" of Ra Horus, falcon-headed war god "Horus guards" wear "frightful helmets" like falcon heads Anubis, jackal-headed funerary god Captain of the guards, Anubis, wears jackal head helmet

Angela Ndalianis examines the mythology behind Stargate SG-1, noting the way it is created by "rewriting centuries-old human mythologies—Egyptian, Norse, Aztec, Greek, Arthurian, Roman—the series takes these myths and 'reboots' them as scientific fact." [ Partial preview] at Google Books. Norse mythology appears in the shape of the "good-guy aliens the Asgard", deriving explicitly in the fiction from Norse Asgard. In her view, the "layered mythology ... borrows shamelessly" from real-world mythologies, giving examples from several of them.

+ Examples from Angela Ndalianis's analysis of borrowings from real-world mythologies in Stargate Mythology Borrowed figures Ancient Egypt Anubis, Apophis, Osiris Ancient Greek Cronus Phoenician Ba'al, Moloc Shinto Amaterasu Celtic Camulus, The Morrígan Hindu Kali, Nirṛti Babylonian Marduk, Ishkur Arthurian legend Merlin, Morgan le Fay Norse Asgard

Franchise-spanning mythology

The film Stargate (1994) establishes that five thousand years ago, the god Ra was an alien who enslaved and transplanted humans from Earth to another planet via the Stargate. Eventually, the people of Earth rose up against him and buried their Stargate. The modern history of Earth and the Stargate begins when it is unearthed in Egypt in 1928. The device is brought to the United States in 1939 to keep it out of Nazi hands and eventually installed in a facility in Creek Mountain, Colorado (Cheyenne Mountain in Stargate SG-1). In the events of the film Dr. Daniel Jackson deciphers the workings of the Stargate and a team is sent through to the planet on the other side.

Stargate SG-1 resumes the story of the film, but establishes that Ra was the leader of a race of parasitic aliens known as the Goa'uld; they took on the role of Earth deities from a variety of mythologies and that there is a network of stargates across the Milky Way. In its pilot episode "Children of the Gods", which takes place a year after the film, Stargate Command is established in response to an attack by the Goa'uld Apophis, and given the mandate to explore other worlds and obtain technologies that can be used to defend Earth. They encounter other races, such as the Asgard, who only masquerade as the Norse gods to primitive cultures until said societies develop enough to see them as they actually are."Red Sky" (Stargate SG-1) Stargate SG-1 further extended the backstory of Earth humans by introducing the Ancients, an advanced race of humans from another galaxy who lived on Earth until approximately 10,000 years ago.

Stargate device

A Stargate is a device that allows practical, rapid travel between two distant locations. The first Stargate appears in the 1994 film Stargate, and subsequently Stargate SG-1 and its spin-offs. In these productions, the Stargate functions as a plot generator, allowing the main characters to visit alien planets without the need for spaceships or any other fictional technology.

Within the Stargate fictional universe, Stargates are large metal rings with nine "chevrons" spaced equally around their circumference. Pairs of Stargates function by generating an artificial stable wormhole between them, allowing one-way travel through. The symbols on the inner ring of the Stargate correspond to constellations and serve to map out coordinates for various destination planets and other locations in space. Most destinations in the franchise are accessed by using only seven chevrons, but the eighth can be used to access other galaxies and the ninth can target special, specific gates.

A typical Stargate measures in diameter, weighs , and is made of the fictional heavy mineral "naquadah". The Stargates were created millions of years ago by an alien race known as the Ancients; their modern history begins when Egyptologist Daniel Jackson deciphers their workings in the Stargate film.

The Stargate device sets apart SG-1 from other science fiction shows by allowing modern-day people to travel to other planets in an instant, although scholar Dave Hipple argued that SG-1 "also deploys [science fiction] stereotypes both to acknowledge forebears and to position itself as a deserving heir". With the help of the central Stargate device, the premise of Stargate SG-1 combines ancient cultures, present-day political and social concerns, aliens and advanced technologies. Near-instantaneous interplanetary travel allows a fundamental difference in plot structure and set design from other series. There is a disjunction between politics on Earth and the realities of fighting an interstellar war.Beeler 2008, p. 269. The Stargate also helps to speed up the exposition of the setting.

Ancients

The race of the Ancients is first mentioned in the Stargate SG-1 season 2 episode "The Fifth Race" as the original builders of the Stargate network and members of the former Alliance of four great races. They were considered humanity's predecessors, originally establishing Earth as their homeworld after they migrated to the Milky Way and having seeded multiple galaxies to allow life to evolve on uninhabited worlds. At the time that the Stargate franchise takes place, the Ancients have long since "ascended", i.e. they shed their physical bodies and live eternally as pure energy on a higher plane of existence with an increased power and capacity for learning. While they are no longer physically present in the universe, their highly advanced technology—including the Stargate—remains behind, all of which has shown to be almost entirely resilient to the decay of time, and has also proven to be the most advanced technology anyone has ever encountered. With humans from Earth as their closest descendants both from a genetic standpoint and an evolutionary standpoint, they have shown the most proclivity in utilizing Ancient technology when they encounter it.

For the first six seasons of Stargate SG-1, the ascended Ancients maintain a strict rule of noninterference in mortal affairs of the material galaxy, and the interactions between humans of Earth and the Ancients are restricted to the outcast Ancient characters Oma Desala and Orlin. The Ancients' ascension was also used as a plot device for the departure of actor Michael Shanks (Daniel Jackson) in season 6 of Stargate SG-1. The fictional background of the Ancients was extended with the franchise's Atlantis mythos that began in the Stargate SG-1 season 6 finale "Full Circle", and which also served as the basis for spin-off show Stargate Atlantis. The Ori arc of Stargate SG-1s seasons 9 and 10 expanded the Ancient mythos further.

Asgard