The Federation-Cardassian Treaty of 2370 was the last in a series of peace treaties negotiated between the United Federation of Planets and the Cardassian Union, bringing an official end to the decades of hostilities between the two powers. It dealt primarily with the status of the worlds along the Federation-Cardassian border, and led to the creation of the Demilitarized Zone.
Among the treaty negotiators on the Federation side was Admiral Alynna Nechayev. Following the near-revolt on planet Dorvan V, when Federation colonists refused to be removed from a world turned over to the Cardassians, Captain Jean-Luc Picard negotiated additional terms which would allow residents to remain on their home worlds under the rule of the rival power.
Many former Federation citizens were maltreated under Cardassian rule, but the Federation refused to act on their behalf. This led directly to the rise of the Maquis. (TNG episode: "Journey's End"; DS9 episodes: "The Maquis, Part I", "The Maquis, Part II")
In 2385, hardliners within the Bajoran government who were advocating the continued persecution of the Cardassian expanded their aims which included the surrender of colonies given to the Union that were party of the Treaty. (ST website: The Path to 2409)