Around 2319, the Cardassian Union occupied Bajor and over the next fifty years enslaved its population and stripped it of its natural resources before they withdrew from the planet. (DS9: "Emissary", "Waltz")
In an alternate universe were the Dominion won the Dominion War Bajor joined the Dominion following the end of the war. The planet's peace and prosperity was used by the Dominion to show the benefits of cooperating and joining the Dominion.
In 2394, the planet suffered a series of devastating natural disasters that were attributed to the removal of the Reckoning Tablet from the planet by the Dominion.
Following the conclusion of the Reckoning a wave of orbs travelled to Bajor and transported all those who were "of Bajor" to the Celestial Temple.
The Dominion investigated the incident and rounded up those remaining on the planet into several camps. After processing these people the Dominion planned to transport everyone off it and simply abandon Bajor. (TFS: Spectrum: "The Final Prophecy")