Order 66

Order 66, also known as Clone Protocol 66, was one of the series of contingency orders that the clone troopers of the Grand Army of the Republic were trained to obey without hesitation. The order branded members of the Jedi Order as traitors to the Republic and called for their immediate execution without question. The order was issued by Supreme Chancellor Sheev Palpatine towards the end of The Clone Wars in 19 BBY.

The command leading to Order 66 can be traced back to the Inception of the clone army. Unbeknownst to the Jedi, each clone trooper was secretly incorporated with a control chip in his brain that could be activated by command. Palpatine obtained the capacity to emit this order as a result of his double identity; He was secretly Darth Sidious, the Dark Lord of the Sith.

With the execution of Order 66, an attempt was made to annihilate the entire Jedi Order. This ranged from young trainees called younglings to experienced masters. The clones, having been programmed to obey any command from the Chancellor, faithfully executed Order 66, turning on their Jedi commanders almost universally across the galaxy.

However, many Jedi managed to escape their initial execution due to varying circumstances, like intuition about their clone soldiers' changed demeanor or sheer fighting ability. This included Jedi like Master Yoda, Obi-Wan Kenobi, and Kanan Jarrus who all ultimately survived the initial purge.

The fallout from Order 66 was vast. With the Jedi Order out of the way, Palpatine transformed the democratic Galactic Republic into the tyrannical Galactic Empire, proclaiming himself as the Emperor. Not just that, but the event also made the rare surviving Jedi some of the most wanted fugitives in the galaxy, with the Empire hunting down and exterminating any remaining survivors in the subsequent Great Jedi Purge.

In essence, Order 66 was a major turning point in the timeline of Star Wars, shaping many events and changing the entire galaxy's dynamics drastically. It allowed for the rise of the Sith and the Galactic Empire, setting the stage for the original and sequel trilogies.