Alliance of four great races

In the science fiction television series Stargate SG-1, the alliance of four great races was an ancient alliance of four advanced species that was built over many millennia and existed before the rise of the Goa'uld.

A planet with a facility where these races used to meet and interact as "a sharing of clans to share a common interest" was discovered by SG-1 in the first season episode "The Torment of Tantalus", when the team was searching for Ernest Littlefield, who had disappeared in 1945. In a large castle-like structure, each race had scribed a wall of text in their own unique language, and a central pedestal projected a hologram containing information composed of atomic forms. The four races developed a common language for communication with each other, using the 146 known (to them) chemical elements as basic symbols. As Dr. Jackson proclaimed, the four races broke everything down to the basics and created "a truly universal language".

In the 2nd Season episode "The Fifth Race," it is learned from the Asgard that the four races were the Alterans, who built the Stargates, the Asgard, the Furlings, and the Nox. As of Unending, the Alterans, Asgard, and Nox have all been seen, with the Furlings still absent from the series. Amanda Tapping said that the Furlings would finally appear in Episode 200,. This was ultimately revealed to be a joke, as the "Furlings" which appeared were within a fantasy scene featuring a television show inspired by the Stargate program.

In the episode 'Unending', Thor declared that the Tau'ri were the Fifth race of the Great Alliance.