From Star Trek: Theurgy Wiki
The Dominion was a major interstellar state in the Gamma Quadrant. Technologically advanced and millennia old, the Dominion was founded under the absolute rule of a group of Changelings known as the Founders, whose will was carried out by the Vorta and the Jem'Hadar. The Dominion was dedicated to imposing the Founders' vision of "order" upon the universe, i.e. bringing all other civilizations under its control. Source: Memory Alpha
At the end of the Dominion War, the Treaty of Bajor was drawn up between the Dominion and the major powers of the Alpha Quadrant. The Dominion retreated back into the Gamma Quadrant. Within their home territory, news of the major defeat spread, leading to some rebellions on subject worlds. They were quickly subdued by the Jem'Hadar.
In 2374, the Great Link learned of the apparent reappearance of the Progenitor and sent a ship to investigate. However when Odo and the others arrived they found the Progenitor was apparently killed by radiation of a supernova. The Great Link dissolved as its individual members gave into their grief and despair and drifted off into space. This left Odo and Laas running the Dominion. Over the next several years, Odo concentrated on running the Dominion while Laas traveled in search of other Changelings to convince them to return. Due to the structure of the Dominion, in which most never even saw a Founder, the day-to-day affairs were largely unaffected. During this time, Odo kept the Dominion borders closed to keep the political situation stable and focused his work on transforming the Dominion into a more peaceful and democratic society.
As of 2381, the borders to the Dominion remained closed.