Following the conclusion of the Yuuzhan Vong invasion, Corellia was rewarded by the Galactic Alliance by the removal of the office of the Governor-General. The Five Brothers were united through a system government, with each planet electing its own Head of State and the system led by Five World Prime Minister Aidel Saxan.
While much of the galaxy had been ravaged by the war, Corellia emerged relatively unscathed, placing it in a position to increase its already impressive economic power and offer reconstruction loans to less fortunate planets. As Corellia prospered, it forgave wartime criminals like Thrackan Sal-Solo, who was subsequently elected the system's Minister of War and Head of State of Corellia, and began to chafe against the Galactic Alliance as it had the New Republic and Galactic Republic before it.
Over the decade following the defeat of the Yuuzhan Vong, Corellia's desire for independence festered and spread, tapping the natural haughty pride of Corellians. Corellia began to delay its conscription contributions and tax payments to the Alliance, while making use of Alliance infrastructure and trade benefits. It also stood against the defense limits imposed by the Alliance, but made no public challenge. Slowly, other industrialized planets like Commenor, Fondor, and Bespin developed similarly overt rebellious streaks.
In secret, Corellia began building a fleet comparable to a planetary assault force, supplied by planets like Adumar that produced weapons in violation of Alliance law. Meanwhile, Corellian scientists worked to bring Centerpoint Station online, hoping to once again use it as leverage. As tensions grew, Corellia's soft rebellion led to the imprisonment of key Corellians like Wedge Antilles, whom Alliance Intelligence perceived as a potential threat.
In 40 ABY, these tensions erupted into war. After the successful assassination of Thrackan Sal-Solo by Han Solo, Boba Fett, and Mirta Gev (acting as mercenaries for Dur Gejjen) the Galactic Alliance offered peace terms to the new government, but they were turned down. Cal Omas reluctantly declared war upon Corellia and her allies.
Unknown to most people except for a few top military personnel, Thrackan Sal-Solo had built a powerful, top-secret fleet in the Kiris Asteroid Cluster shipyards. A day after the assassination of Sal-Solo, the new Corellian Government appointed Wedge Antilles to command this fleet, which included several new Corellian Dreadnaughts. They also asked Han and Leia Solo to come to the Kiris Asteroid Cluster to receive orders. Much to Han's surprise, they asked him to travel to Hapes to discuss an alliance with Tenel Ka, the Queen Mother of the Hapes Consortium. Unfortunately for the Corellian government, they discovered a plot to overthrow Tenel Ka and resolved to prevent it.
They accomplished exactly that, and more: they uncovered information on the "Heritage Council", the actual would be usurpers, had hired Aurra Sing, the legendary Jedi killer and former Jedi Padawan. They met up with Lady Morwan, The Heritage Council's agent, and agreed to take her to Hapes to meet up with the leader of the Heritage Council, Aleson Gray. During the subsequent battle between loyal Hapan forces (including the Anakin Solo) and the Heritage Council Armada. Aurra Sing somehow penetrated the Anakin's defenses to assassinate Allana, Jacen Solo and Tenel Ka's daughter, and the Chume'da of the Cluster. Jacen intercepted her (with a little help from Allana herself) and imprisoned her.
Following the failure of the assault fleet at Hapes, Dur Gejjen and his government replaced the reticent Wedge Antilles with Admiral Genna Delpin, and waited for other worlds to throw their support behind the movement. Luckily for Gejjen, the Sith Lumiya was operating on her own agenda, wishing to bring the Galactic Alliance into a larger conflict. By manipulating people and events, she encouraged Bothawui and Commenor, two planets which had already voiced support for Corellia's plight, to assault the GA blockade. Following the successful rout of the Alliance forces under Jacen Solo and Admiral Tarla Limpan, Corellia secured her home system, Five Worlds was dissolved and declared itself the Corellian Confederation, later renamed at the bequest of Bothawui and Commenor to the more simple 'Confederation'.
When the Second Galactic Civil War had ended in 41 ABY the Confederation surrendered to the Galactic Alliance but did not rejoin.
The military forces of the Five Worlds consisted of the resurrected CorSec and the Corellian Defense Force, under the oversight of the Ministry of War and the leadership of a Minister of War. Later the title of Supreme Commander would succeed Minister of War as Commander-in-Chief and Corellian High Command would succeed the Ministry of War for oversight.
After the start of the war, the Corellian leadership established a plan to draw the Hapes Consortium into the alliance. By the time of the Battle of Hapes, Bothawui was outfitting three cruiser fleets for Corellian crews, with Nal Hutta close behind.
- The Complete Star Wars Encyclopedia