Jedi-Sith War

During the era referred to as the Hundred-Year Darkness, a renegade Jedi developed the belief that the true strength of the Force was not found in meditation and inactivity, but instead, the full potential of the Force could only be unlocked by embracing the dark side of the Force. This idea was rejected by the Jedi High Council, who banished the fallen Jedi from the Jedi Order. Despite this, the rogue Jedi attracted followers and established a new group that would eventually become the Sith. Subsequently, war erupted between the Jedi and the Sith, during which the Sith established empires that relied on slavery for their existence, but in the end, the Jedi and the Galactic Republic emerged victorious. Nevertheless, the Jedi and the Sith continued to fight across the millennia.

The Jedi found themselves in conflict with the Mandalorians, yet the Old Republic persisted in repelling the Sith's attacks as the Old Republic crumbled, ushering in a dark age.

During the Jedi-Sith War, the Jedi's Army of Light launched campaigns against the Sith's Brotherhood of Darkness. The Sith utilized a dark side fortress on Ando at some point during the war. The Sith seized control of Coruscant at one point during the conflict, but the Jedi later freed the world. Although the Sith nearly succeeded in conquering the Republic, they were vanquished on Ruusan in the year 1032 BBY.

The ancient Sith Order's membership was decimated by "uncontrolled ambitions and internal strife" as ambitious Sith Lords fought for power and supremacy, which, in turn, gave the Jedi a chance to remove the Sith as a "credible threat" to the Republic. The result was the almost complete annihilation of the Sith; however, the Sith Lord Darth Bane prevented the Sith from going extinct, surviving the Jedi-Sith War as the last member of his Order. Bane, in fact, orchestrated the demise of his own Order. Bane believed that the Sith Order had grown weak as a result of internal conflict and needed to be rebuilt.

Despite the fall of Coruscant having a devastating effect on the Republic, it re-established its capital on the ecumenopolis by the time the Jedi-Sith War ended. The Republic's pre-modern form declined and fell as a result of years of full-scale war with the Sith. The Republic was not only restored but also reinvented as the "modern Galactic Republic" after the Sith were nearly destroyed.

The restoration of Coruscant as the Republic's seat of power marked the official reset of galactic history, which then began anew with the re-founding of the Republic in its modern form. While this version of the Republic was regarded as the "most recent evolution" of the government that had existed for millennia, the history preceding the Republic's rebirth, including the Jedi-Sith War, became a forgotten dark age known collectively as the "Old Republic." The Galactic Accord of Systems was established around 972 BBY in case another war broke out.

The Jedi-Sith War was remembered as the last war in the history of the Old Republic before the Republic's rebirth, as well as Darth Bane's creation of the Rule of Two. A History of Persuasive Art in the Galaxy, a book on the history of propaganda that also featured the works of the Bith artist Janyor, The Secrets of the Jedi by Jedi Master Luke Skywalker, and The Secrets of the Sith by the Dark Lord of the Sith Darth Sidious were among the accounts that chronicled the war. These works, however, focused more on the war's long-term consequences than on its events.

The Republic, under the protection of the Jedi Order, was successful in uniting much of the galaxy under the authority of the Galactic Senate on Coruscant. Following the Jedi-Sith War, the Republic Military was demobilized, leaving the Republic in a demilitarized state until the Grand Army of the Republic was formed at the conclusion of the Separatist Crisis. The Republic Era was largely devoid of armed conflicts, with the exception of a few isolated incidents that were put down by the Jedi's peacekeeping efforts. As a result, it was also known as the "Great Peace."

The Republic reached the height of its power during the High Republic Era, a sub-era within the larger Republic Era that lasted approximately a thousand years. The Republic, driven by a sense of manifest destiny, pursued an expansionist policy aimed at uniting the entire galaxy under the Republic banner.

The era of democratic governance lasted for a millennium until the Republic was replaced by the Galactic Empire at the end of the Clone Wars in 19 BBY. According to the book A History of Persuasive Art in the Galaxy, the Republic Era was "the last era of peace" in galactic history.

Having defeated the Sith, the Jedi expanded their role in the galaxy, working closely with the Senate of the reborn Galactic Republic in the pursuit of peace. Generations of Jedi dedicated themselves to the cause of peace, promoting justice and harmony across the known galaxy as peacekeepers of the Republic. The Jedi Knights, assisted by the Republic Judicials, were in charge of maintaining law and order, primarily by mediating conflicts to find peaceful solutions between various rival factions and planets, as well as serving as interplanetary law enforcement by pursuing wanted and dangerous criminals, pirates, and smugglers.

The Jedi Order reached the height of its power during the High Republic Era, a time when the Order expanded its influence to the galaxy's Outer Rim Territories. Furthermore, the Order maintained its presence on Coruscant, the galactic capital of the Republic, using the Jedi Grand Temple as its headquarters and a training center for the education of future generations of Jedi in the ways of the Force. The Jedi pledged their allegiance to the Senate and the Republic as a whole, officially serving as the Senate's emissaries and enforcers when necessary. The Order, however, retained its autonomy and was governed independently by the Jedi High Council.

Darth Bane, realizing that his fellow Sith Lords were destroying themselves with their lust for power, reformed the Order by establishing the Rule of Two. The Rule of Two, a successor to the Doctrine of the Dyad, stipulated that only two Sith Lords—a master and an apprentice—could exist at any given time to prevent infighting. He also created the Rule of Two so that the Sith could operate in secret, working from the shadows and favoring guile and conspiracy over brute force until it was time for them to exact revenge, rise again, and subjugate the galaxy.

Although the Jedi discovered Bane and learned about his creation of the Rule of Two, the Sith Lord's defeat convinced them that his plans to restore the Sith to power had been thwarted. Unbeknownst to the Jedi, the reformed Sith Order survived Bane's death, who was killed by his apprentice, Darth Zannah. As a result, the Sith survived for another millennium, cycling through generations of Sith Lords who completed their rise in the dark side by replacing the masters who had trained them.

Bane was the last Sith Lord to be buried in the Valley of the Dark Lords on Moraband, the Sith's traditional home planet, which they abandoned after it was scarred by numerous wars. For a thousand years, the Sith remained hidden, their survival unknown to the Jedi, as they plotted their revenge against the Jedi Order. The Sith remained a distant memory until the rise of Darth Sidious, a Dark Lord of the Sith, and his apprentice, Darth Maul, in the waning years of the Galactic Republic. Sidious's machinations brought about the fulfillment of the Grand Plan that began with Bane; the Jedi Order was eliminated, and the Republic became the Empire, with Sidious as the reigning Galactic Emperor. Sidious ruled the galaxy for a little over twenty years with his final Sith apprentice, Darth Vader, by his side as his right-hand man and personal enforcer.

Vader had once been known as Anakin Skywalker, a Jedi Knight prophesied to be his Order's Chosen One in order to bring balance to the Force. Vader, however, would return to the light side after years of living as a Sith Lord at the urging of his son, Jedi Knight Luke Skywalker, during the Battle of Endor in 4 ABY. The returned Anakin Skywalker betrayed and killed Sidious, who secretly managed to cheat death using the power of transference. Sidious's empire would be formally defeated a year after his death with the Battle of Jakku in 5 ABY. Sidious announced his return to the galaxy in 35 ABY and attempted to create a new regime, only to be defeated at the Battle of Exegol by his granddaughter, the Jedi Rey.

The Jedi-Sith War was first mentioned in the 2016 reference book Star Wars Propaganda: A History of Persuasive Art in the Galaxy. It was first identified in the 2019 Fantasy Flight Games reference book Rise of the Separatists.

In Star Wars Legends, this conflict was known as the New Sith Wars, which lasted from 2000 to 1000 BBY and first appeared in Dark Forces: Jedi Knight.

George Lucas claims that there was never a Jedi-Sith war and that the Sith destroyed themselves, not the Jedi. "'Oh, well, there was a war between the Jedi and the Sith.' Well, that never happened. That's just made up by fans or somebody. What really happened is, the Sith ruled the universe for a while, 2,000 years ago. Each Sith has an apprentice, but the problem was, each Sith Lord got to be powerful. And the Sith Lords would try to kill each other because they all wanted to be the most powerful. So in the end they killed each other off, and there wasn't anything left."