- "We are the select few who refuse to be carried by the Force, and who carry it instead. Thirty in a millennium, rather than the tens of thousands fit to be Jedi."
- ―Darth Plagueis[src]
The Order of the Sith Lords, also known as Bane's Sith Order, Banite Sith, or simply the Sith, was an ancient organization of Force-sensitives who utilized the dark side of the Force. Founded approximately one thousand years before the Battle of Yavin by the Sith LordDarth Bane, it was intended to replace the Brotherhood of Darkness and institute a rebirth of the Sith. The guiding principle of the Order was the Rule of Two, which was developed by Bane through the teachings of Darth Revan's Holocron. Under this new tenet, only two Sith Lords were allowed to exist at any given time; a master and an apprentice. The Rule stipulated that after learning everything the master had to teach, the apprentice would attempt to kill the master and take an apprentice of their own. The intended effect of this rule was to ensure that each successive master would be stronger than the last. Ultimately, Bane intended that his successors would be able to amass enough power in secret to engineer the fall of the Republic and the destruction of the Jedi Order.
Bane's expectations of the new Order were met with his death at the hands of his own apprentice, Darth Zannah. The tradition was carried on over the next millennium, even though many Sith who followed in Bane's lineage were appalled at the thought of being slain by their own apprentices. After centuries of operating in secrecy, the Grand Plan for revenge was initiated by the Sith Lords Darth Plagueisand Darth Sidious. Sidious, who usurped his Master's position, ultimately fulfilled Darth Bane's dream: the return of Sith dominance throughout the galaxy. With the betrayal and near destruction of the Jedi Order, Sidious dissolved the Galactic Republic and replaced it with the Galactic Empire. Ruling as emperor in his public guise as "Palpatine".
(Source Star Wars wika)