The Alliance of Independent Systems was an interstellar government, headed by a Chairman, in the Journal of the Whills, Part I. It employed the Jedi-templar Mace Windu as Warlord until he was ousted from the position by his political enemies.
The Galactic Empire was another, possibly enemy, government at this time.
Behind the scenesEdit
This entity was created in George Lucas's earliest writing about the Star Wars universe, the Journal of the Whills, an in-universe narrative written by Chuiee Two Thorpe of Kissel, Mace's padawan learner. The Rebel Alliance was directly derived from it as the story was rewritten into a script, but it may be a forerunner of the Confederacy of Independent Systems as well, at least in nomenclature.
Though the Galactic Empire was always a villainous force in the final script, in the later rough draft script, the Jedi served the Emperors until fairly recently, and the Galactic Republic had not yet been invented. Instead, the pre-existing Empire had declined into barbarism and decadence.