The Rule of Two was a Sith philosophy established by Sith Lord Darth Bane in order for the Sith to operate in secret and eventually get revenge on the Jedi Order, following their near annihilation in the Jedi-Sith War. Inspired by the concept of a Force dyad, the rule mandated that only two Sith Lords could exist at any given time: a master to represent the power of the dark side of the Force, and an apprentice to train under the master and one day fulfill their role. The philosophy of two governed the Lords of the Sith.