|For information relating to the Dominion in Star Trek canon, see Dominion. For more information relating to the Dominion in Star Trek fanon, see Dominion.|
The United Federation of Planets was first made aware of the Dominion when the Bajoran wormhole, discovered by the Deep Space 9 crew in the Bajoran system in the Alpha Quadrant, allowed access to the Idran system in the Gamma Quadrant. (Star Trek: Deep Space Nine; Star Trek: The Prospect Chronicles)
After the disastrous confrontation between the Dominion's Jem'Hadar and the USS Odyssey (NCC-71832) a year earlier, Rear Admiral Alexandra de Groot tasked the crew of the USS Prospect (NCC-60056) with making first contact with the Dominion in 2371. It ended in disaster. (Star Trek: Deep Space Nine: "The Jem'Hadar"; Star Trek: The Prospect Chronicles: "Pure Massacre")
Captain John Greene faced court-martial later after the loss of the USS Prospect during a Special Operations mission to the Gamma Quadrant to make first contact with the Dominion's Founders. (Star Trek: The Prospect Chronicles) This is assumed as Greene was found innocent as he was given command of the Galaxy-class USS Prospect-A later in the same year.
Later that same year, Drs. Henrik and Samantha Delaney installed their folded space drive prototype aboard the USS Rutherford, which malfunctioned, and the Rutherford jumped from the Alpha Quadrant to the Gamma Quadrant.
The Jem'Hadar attacked as the Rutherford crew attempted to recharge the device. As the Jem'Hadar boarded, Henrik Delaney and a security detail detached the folded space drive prototype, making a run for it in a shuttlecraft.
The Jem'Hadar pursued, so Delaney ordered the shuttlecraft to land on New Bajor. The tactic failed and the Jem'Hadar tracked them down. In a last ditch effort to prevent the device from falling into Dominion hands, Henrik Delaney rigged the device up to the shuttlecraft and activated it.
The USS Prospect-A infiltrated Dominion space in order to regain the folded space device, but their investigations led them to New Bajor, where they found evidence Delaney had activated it. They destroyed the Rutherford and were severely damaged in battles with the Jem'Hadar before returning through the Bajoran wormhole to Deep Space 9. (Star Trek: The Prospect Chronicles: "Directive")
The Dominion War was fought between the Dominion and some Alpha Quadrant allies, including the Cardassian Union and the Breen Confederacy, and major Alpha Quadrant powers, including the Federation, Klingon Empire, Romulan Star Empire, and the Bajoran Republic, between 2373 and 2375. (Star Trek: Deep Space Nine)