The Soldier's Way
The Rebel Alliance
The first antecedents of the Alliance to Restore the Republic are told during the events of Revenge of the Sith. It is explained (in scenes that were mostly cut from the theatrical version) that the Delegation of 2000 is a group of Senators who are disgruntled about the already unjustified extraordinary powers of Supreme Chancellor Palpatine as the Clone Wars were waning. The group included Padmé Amidala, Garm Bel Iblis, Mon Mothma, and Bail Organa, amongst others. Amidala was, at the time, the most famous and prominent of the group, and was thus their spokesperson, but she realized that this made her a target and later advised the others to go quiet in their dissent and exclude her from any future proceedings. The young senator died in premature childbirth not long after her last-ditch attempt to prevent Anakin Skywalker’s fall.
The TV series Star Wars Rebels, set five years before A New Hope and fourteen years after the fall of the Galactic Republic and the Jedi Order in Revenge of the Sith, chronicles the beginnings of the rebellion against the Galactic Empire. The show focuses on a motley group of rebels (all of whom have been affected by the Empire in one form or another) that band together aboard a freighter starship called the Ghost. By the end of the first season, it is revealed that there are various cells that are resisting the Empire, with Bail Organa and former Jedi Ahsoka Tano both playing a role in coordinating them.
Galactic Civil War
During the events of A New Hope, the Alliance learns of the construction of the Death Star, an enormous battle station intended to secure the Empire’s power. Operation Skyhook, a military campaign commanded by Princess Leia Organa, successfully steals the schematics of the station, but her ship is crippled and captured by the Imperial fleet while attempting to deliver them. Princess Leia is held hostage for a time by the Emperor’s second in command, Darth Vader, but is rescued by Luke Skywalker, Han Solo, Chewbacca, and Obi-Wan Kenobi, who are able to deliver the station schematics to the Alliance. This leads directly to the Alliance’s victory in the Battle of Yavin and the loyalty of Luke, who becomes the Rebellion’s only remaining member with training in the Force.
In The Empire Strikes Back, the Alliance suffers a crushing defeat on Hoth when one of their main command centers, Echo Base, is overrun by the Empire’s 501st Legion. The remaining forces of the Rebellion are forced to stay mobile, using Admiral Ackbar’s flagship, the Home One, as their headquarters.
By Return of the Jedi, the Rebel Alliance has regrouped and learned that a new Death Star is being constructed, and will be completed under Emperor Palpatine’s personal supervision. Mon Mothma has Admiral Ackbar and Lando Calrissian command the Alliance fleet and dispatches Han Solo and Princess Leia to disable the station’s defenses, while Luke distracts Vader. The Alliance subsequently wins the Battle of Endor, in which Darth Vader, Darth Sidious, and much of the Imperial hierarchy are destroyed. Thus, the Empire is essentially defeated, and the Rebellion liberates most of the galaxy.
By The Force Awakens, the New Republic has formed from the Rebellion. The Resistance, an army backed up by the New Republic, is formed to stand against the First Order, a new military power formed by remnants from the old Empire.