The Federation-Cardassian War was a conflicts between the United Federation of Planets and the Cardassian Union that started in the middle of the 24th century. A cease-fire was reached by 2363, though skirmishes continued until 2366 and a more permanent treaty was signed in 2367. (Star Trek: Pendragon, VOY: "Dreadnaught")
Despite their and the Bajorans' mutual enmity with the Cardassians, the Federation refused to involve itself in the Occupation of Bajor, which continued throughout the Federation-Cardassian War. (TNG: "Ensign Ro")
In 2370, a final treaty was signed by the two sides, establishing a demilitarized zone between the two parties, creating a new border and clarifying ownership of planets such as Dorvan V. (TNG: "Journey's End") The Miltoans were involved in this process. (Star Trek: The Cantabrian Expeditions)
Though unfailingly supportive of the peace process, Ambassador Savin th'Vayhr strenuously opposed certain terms of the Federation-Cardassian Treaty of 2370. In a formal address to the Federation Council, he disavowed the abandonment of Federation colonists and called the treaty "a shameful display of political convenience and self-interest." (Star Trek: Pendragon "The Distant Fire")
The Maquis were created by disgruntled Starfleet officers, crewmen and Federation civilians who felt "sold out" by the Federation with the treaty and the creation of the DMZ. (TNG: "Journey's End"; DS9: "The Maquis")
Despite the truce, tensions still remained high between the two powers after the signing of the treaty. Three years later the Federation and Cardassians would be at war again, taking different sides in the Dominion War after Gul Skrain Dukat sold out his government to the Dominion. (Star Trek: Deep Space Nine seasons 5-7)
- Federation-Cardassian War article at Memory Alpha, the canon Star Trek wiki.
- Federation-Cardassian War article at Memory Beta, the non-canon Star Trek wiki.