Operation: Knightfall

Operation: Knightfall, which took place in 19 BBY immediately before the end of the Clone Wars, was one of the first conflicts of the Great Jedi Purge. After assisting in the death of Jedi Master Mace Windu and submitting to the tutelage of Dark Lord of the Sith Darth Sidious—known to the galaxy as Palpatine, Supreme Chancellor of the Galactic Republic—Jedi Knight Anakin Skywalker fell to the dark side and was anointed Darth Vader. Just afterward, Vader was assigned a detachment of the 501st Legion's clone troopers and was tasked with storming the Jedi Temple on Coruscant alongside them. This massacre, as well as the mandate given to the clones instructing them to kill their Jedi officers in the field, marked the beginning of a galaxy-wide hunt for the Jedi. Most of the Jedi inside the Temple were executed by the invaders while the Temple burned, and within minutes of the Purge's inception, much of the Jedi Order was wiped out.

During the fighting, Vader altered a beacon that alerted Jedi across the galaxy—the ones that had not already fallen to the clones in their ranks—that the Clone Wars were over and ordered them back to the Temple, where a garrison of clone troopers lay in wait to finish them off. All of the Jedi who complied with the beacon's mandate were killed by squads of clones, some of whom were disguised as Jedi themselves. To prevent deaths, two surviving Jedi Masters, Obi-Wan Kenobi and Yoda, infiltrated the Temple and switched the beacon, changing the message to ward away any surviving Jedi and instructing them to go into hiding. With the operation's completion, the bodies of the slain Jedi were publicly burned in a massive pyre in front of the Jedi Temple's public entrance.

Text and facts from the “Operation: Knightfall/Legends” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.