The Detapa Council was the civilian governing body of the Cardassian Union. Created to oversee the actions of Central Command and the Obsidian Order by the 24th century the Council was virtually powerless.
One of the goals of the Cardassian dissident movement was to restore the Detapa Council to power. In 2372, they succeeded in this goal after the destruction of the Obsidian Order the year before a popular uprising toppled Central Command. The Klingon Empire took this as a sign that the Detapa Council was infiltrated by Changelings and used this as a pretext for launching an invasion of Cardassia.
When the Klingons broke through the Cardassian Guard and made their way to Cardassia Prime Legate Dukat evacuated the Council to rendevzous with the USS Defiant. Despite Klingon attempts to destroy the ship transporting the council they were safely evacuated to the Defiant and given refuge on Deep Space 9, where the Klingons again failed to capture them.