Rebel Alliance

The Alliance to Restore the Republic (commonly known as the Rebel Alliance, and, informally, as the Rebellion) is an interstellar faction of the fictional universe of Star Wars.

As a direct reaction to the Galactic Empire, the Rebel Alliance warred throughout the Star Wars galaxy for restoring the ideals and format of the Old Republic. The Rebel Alliance was featured in the original trilogy of films, A New Hope, The Empire Strikes Back, Return of the Jedi, with the protagonists of the films being part of the Rebellion. The origins of the Rebel Alliance are depicted in the Disney XD series Star Wars Rebels, set between Revenge of the Sith and A New Hope

Between Return of the Jedi and The Force Awakens, the Rebel Alliance was reorganized as the Republic of Free Systems, with Leia Organa being appointed chancellor. The Republic waged a 20-year war with the Galactic Empire, taking back control of nearly half of the Galaxy. Mysteriously, Chancellor Organa called for a peace treaty, leaving the Galaxy in a state of uneasy truce, with a few select worlds such as Tatooine being neutral ground for both the Republic and the Empire.

Trivia

 * While it is informally reffered to as "rebellion", it means an act of violent or open resistance, to an established government or ruler.