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 existed before the rise of the Goa'uld.

A planet with a facility where they 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". Dr. Daniel Jackson was viewing Pentagon archival films of the Stargate Program vintage 1945 when he saw an American scientist named Ernest Littlefield walk through an active Stargate. In a large castle-like structure each race had scribed a wall of text in their own unique language. At least initially, each race was unable to communicate to the other so they developed a common language using the 146 known (to them) chemical elements as basic symbols. Each time the "tablet" was touched a new "page" would appear in the form of a combination of floating molecules made up of specific elements (e.g. hydrogen, sodium, silver, iron, etc.) which itself was the method each race used to first communicate with the other. As Dr. Jackson proclaimed, the four races broke everything down to basics and created "a truly universal language".

In the 2nd Season episode "The Fifth Race", we learn that the four races were the Ancients, who built the Stargates, the Asgard, the Furlings and the Nox. Avid viewers have met and become familiar with all but the Furlings as of the end of Season 8.