End of the Occupation and Discovery of the Bajoran Wormhole

In 2369 the Cardassians ended their occupation of Bajor and stripped the orbital station Terok Nor before leaving. At the request of Bajor's provisional government, the Federation took over the station, renamed Deep Space 9, under Commander Benjamin Sisko, with the Bajoran resistance veteran Kira Nerys as his first officer.

Kai Opaka, Bajor's spiritual leader, entrusted Sisko with one of the sacred Orbs. Following clues it provided, Sisko and Lieutenant Jadzia Dax discovered in the Denorios Belt the first known stable wormhole, a passage leading some seventy thousand light-years to the Gamma Quadrant. Inside it lived non-linear beings whom Bajorans worshiped as the Prophets; Sisko, who taught them about linear time, came to be regarded as their Emissary.

Deep Space 9 was moved to the mouth of the wormhole to claim it for Bajor, and a Cardassian attempt to seize it failed when the station held out until Sisko returned. Overnight Bajor became a strategic crossroads for trade, exploration and, eventually, contact with the Dominion.