The Great Jedi Purge, also known as Order 66, is a plot element in the 2005 film Star Wars Episode III: Revenge of the Sith, as well as the Star Wars Expanded Universe. In the film, the Jedi are nearly exterminated by the order of the Sith lord Darth Sidious.
At some point between the known events of Episodes II and III, members of the Jedi council began to suspect Chancellor Palpatine was tied to Sidious and Count Dooku's Separatist army. In Revenge of the Sith, Jedi Master Mace Windu openly states to the Jedi Council that he no longer trusts the Chancellor; Obi-Wan Kenobi expresses similar misgivings.
Anakin Skywalker, then believed to be the "Chosen One" of Jedi prophecy, finds out that Palpatine is actually Darth Sidious, the Dark Lord of the Sith for which the Jedi have been searching for more than a decade. Anakin reveals this information to Windu, who then leads a small team of fellow Jedi Masters - Agen Kolar, Saesee Tiin and Kit Fisto - to apprehend Sidious. In the ensuing lightsaber duel, Sidious quickly and effortlessly kills all but Windu, who defeats him. As Windu reasserts Palpatine's arrestment, however, Anakin suddenly enters the room while Palpatine is apparently pleading for his own life. Palpatine had long been nurturing the young Jedi's desire for power and had recently roused Anakin's fear for the safety of his pregnant wife, Padmé Amidala. Before Windu can strike down the Chancellor after fending off a sneak attack by the Darth, Anakin severs Windu's hand with his lightsaber; Sidious springs to life, blasting Windu with a torrent of Force lightning, which throws him out the window to his apparent death. Agen Kolar, being the first to die at the hands of Darth Sidious is effectively the first victim of the Great Jedi Purge, followed within moments by Tiin and then Fisto.
It was mentioned by George Lucas in the Revenge of the Sith DVD commentary that Anakin thought he was doing the right thing saving Palpatine’s life when he cut off Windu's hand with his lightsaber. However, Anakin did not think that Palpatine would kill Windu, and as a result of Windu's death Anakin believed that he had gone too far to be forgiven. To save his life, he had no other choice but to join with Palpatine.
Darth Sidious gives Anakin the Sith name Darth Vader, and orders him to exterminate the Jedi. He sends his new apprentice to the Jedi Temple along with the 501st Clone Trooper Legion to kill all of the Jedi there. Palpatine said that if Vader carries out his commands, he will be strong enough in the dark side to save Padmé, and so Vader complies without a second thought. While the newly turned Dark Lord is completing this task, Palpatine instructs the clone troopers to carry out Order 66, an order implanted in them to kill their Jedi generals when commanded.
Among the most notable Jedi killed at the very beginning of the purge are Ki-Adi-Mundi, Aayla Secura, Barriss Offee, Luminara Unduli, Plo Koon, Stass Allie, and Traavis.
Returning to Coruscant, Masters Yoda and Obi-Wan Kenobi enter the Temple long enough to re-encode a secret retreat signal being broadcast by the in-house communications ordering all Jedi to return to the Jedi Temple, deciding to warn all surviving Jedi about the treachery and to take precautions. During a special Senate session, Palpatine declares the Jedi traitors. He then reorganizes the Republic into the Galactic Empire, declaring himself Emperor of the Galaxy.
Realizing they are in no position to oppose the Empire for the time being, Kenobi and Yoda go into hiding. Additionally, they decide that Luke and Leia, the children of Anakin and Padmé (who had died giving birth to them), would need to be raised separately and in hiding in order to protect them from the Empire. Bail Organa volunteers to adopt Leia with his wife on Alderaan. By Yoda's decision, Luke would be raised by Anakin's stepbrother, Owen Lars on Tatooine, while Kenobi watches over him from a distance. Yoda chooses exile on a planet in the Dagobah System.
Kenobi and Yoda are not the only Jedi to survive. An'Ya Kuro, who was known to have lived for another 20 years after the Jedi Purge, hid on Cophrigim 5. Darth Vader personally went to kill her. After being crushed by a tree she told Vader that he could still release Anakin from the dark side.
In the game The Force Unleashed, it is revealed that several other jedi, including Jedi Master Shaak Ti had survived the initial purge, only to be later killed by Vader's apprentice Starkiller. Furthermore A'sharad Hett had turned to the dark side in the act of being the darth lord in the series.
According to the The Hand of Thrawn Duology, Palpatine begins killing Jedi before the Great Jedi Purge occurs. Shortly after the Battle of Naboo (depicted in Star Wars Episode I: The Phantom Menace), the Jedi Council approved the "Outbound Flight Project". A group of Jedi masters would travel to the edge of the galaxy and attempt to use the Force to punch through the hyperspace turbulence surrounding the galaxy, thereby allowing them to attempt contact with life in other galaxies.
The ship is intercepted on Palpatine's command and all hope of contacting life outside the galaxy ended. It is known that the Chiss who would become Imperial Grand Admiral Thrawn was involved in the interception of this ship.
Timothy Zahn has two new novels, Survivor's Quest and Outbound Flight, to further elaborate the Outbound Flight Project.
One of those Jedi Masters killed by Thrawn is Jorus C'Baoth. His clone, which serves the Empire, is subject to fits of insanity and eventually betrays Thrawn in the Heir to the Empire series.
X-Wing Rogue Squadron pilot Corran Horn discovers a museum chronicling members of the Jedi Order whom Palpatine had killed, filled with destroyed statues of former Jedi on Coruscant.
In the strategy game Star Wars: Galactic Battlegrounds, after crashlanding on the planet of Krant, Princess Leia Organa and C-3PO, along with a small group of rebels, discover a Jedi who survived the purge, Echuu Shen-Jon. He helps them win many victories on Krant, then travels with them to the Geddes asteroids to reclaim a Jedi artifact. When they land there, they are helped by a small army of Wookiees. In this mission, Shen-Jon dies at Darth Vader's hand, sacrificing himself so Leia and the other Rebels could escape. Also, in the game Star Wars Battlefront II, some Jedi survive the purge and were killed by Stormtroopers on Naboo.
In the expansion, it is revealed that he stays on Krant after the battle on Geonosis (depicted in Star Wars Episode II: Attack of the Clones). During that battle, he loses his Padawan, Stam Reath, and tries to avenge him by following the killer, Sev'Rance Tann, to Krant. His Padawan for this mission is Naat Reath, Stam's sister. Naat is captured and Echuu attacks Tann and her droid army, overtaken by the dark side. Helping him in this was a small group of Wookiees, who were left on Krant when their leaders evacuated. He succeeds in killing the Dark Jedi, but at the cost of many clones and Wookiees. After realizing that he let the dark side overtake him, he stays on Krant in self-exile, narrowly avoiding the Great Jedi Purge, which he refers to as "the Jedi Massacre."
In the New Jedi Order series, Vergere is revealed as a Jedi Knight from before the Empire. She was sent on a mission to investigate the living planet Zonama Sekot, where she encounters the Yuuzhan Vong. Considering them to be a threat, Vergere convinces them to take her as an advisor and jester of sorts to their Warmaster, Tsavong Lah. The Great Jedi Purge takes place after she leaves with the Yuuzhan Vong. Her connections to the Old Jedi Order prove important in the training of Jacen Solo and allow her to provide Luke Skywalker with a small view of the old order. Before she can finish completely instructing them, she dies protecting Jacen from Tsavong Lah's forces.
In Star Wars: Legacy, a Sith named Darth Krayt sends his legions to destroy the Jedi Temple at Ossus. They massacre the Order, missing half of the Jedi, including: