The Changelings were once a peaceful race but what they saw as consistent persecution by solids led them to retreat to isolation and distrust and fear solids. In order to protect themselves from a seemingly hostile galaxy they founded the Dominion with a mandate to "bring order to the galaxy" and control the solids, thereby removing them as a threat to the Founders.
To aid in their goals the Dominion genetically engineered two subservatent species to serve them: the Vorta and the Jem'Hadar. The Vorta would act as administers, scientists, diplomats and military commanders while the Jem'Hadar were engineered as soldiers. Both races were created with the belief that the Founders were gods as a method of control.
By the late-24th century, many members of the Dominion considered the Founders to by a mythical species due to the Founders preference for isolation and letting the Vorta run the Dominion. The bulk of the Founders lived on a rogue planet in the Omarion Nebula in what was referred to as the Great Link, which was a vast sea of Founders in their nature state.
In 2371, the Federation made contact with the Founders after sending the USS Defiant to find them and discovered the true nature of the Founders as shapeshifters. At least from this point and possible before several Founders entered the covertly entered the Alpha Quadrant.
Later that year the Obsidian Order and the Tal Shiar attempted to wipe out the Founders with a surprise attack against their homeworld. However, a Founder had infiltrated the group allowing the Founders to prepare. They evacuated their homeworld and moved to a new planet and sprung their own trap, wiping out the enemy fleet.
With the risk of Founder infiltration in the Federation, Section 31 created a morphogenic virus to wipe out the Founders. They infected Odo in 2372 and using him to spread the disease through linking with other Founders. By 2375, nearly all the Founders were infected and dying of the disease. A cure was found for the disease, which Odo shared with the Great Link as part of an agreement with the Female Changeling to end the Dominion War.
- ↑ 1.0 1.1 1.2 DS9: "The Search, Part I"
- ↑ 2.0 2.1 DS9: "The Search, Part II"
- ↑ DS9: "Hippocratic Oath"
- ↑ 4.0 4.1 DS9: "Treachery, Faith and the Great River"
- ↑ DS9: "Improbable Cause"
- ↑ DS9: "The Die is Cast"
- ↑ DS9: "The Adversary"
- ↑ DS9: "Homefront"
- ↑ DS9: "Apocalypse Rising"
- ↑ DS9: "Extreme Measures"
- ↑ DS9: "What You Leave Behind"