The Faunus Rights Revolution (also referred to as the Faunus War) was a revolution staged by the Faunus in retaliation against Humans trying to centralize their species in Menagerie. As a result of winning the war, Faunus are allowed to live within the four Kingdoms. It is not to be confused with the Great War, an earlier and far larger conflict based around social and cultural ideology, rather than racial politics.
Not much has been disclosed about the Faunus War, nor has there been a definitive timeline given. It is known that it was a fairly large-scale conflict that lasted at least three years and took place after the Great War.
The cause of the war is attributed to the Humans' attempts to confine Faunus to a continent of Remnant known as Menagerie, and countermand the rights the Faunus earned in their participation in the Great War. Given that Faunus are seen living among Human populations in the present, it can be deduced that the war was at least successful in preventing the imposition of these policies.
Although little information is available regarding the actual chronology of the war, the Battle of Fort Castle in the third year of the war is widely regarded as the turning point. The inexperienced leader of the Human forces, General Lagune, attempted to catch the enemy off-guard in a nocturnal attack. However, the Faunus were able to leverage their advantage of near-perfect night vision and soundly defeated the larger army.
Despite whatever material gains the Faunus achieved during the war, they remain a subject of discrimination, as exemplified by Blake's mention of Human shops refusing to serve Faunus shortly prior to the start of the series. The treatment they receive varies from place to place, but locations like Beacon Academy and Vacuo appear to be host to less discrimination than others.
Some time after the war, the White Fang organization was set up and intended to serve as a prospective "symbol of peace and unity between Humans and the Faunus". However, this idea was evidently abandoned in the face of continuing discrimination.
Following the Great War, efforts were made for everyone worldwide to reach compromise, in the hopes that the Kingdoms would never go to war again. One of these efforts involved giving Faunus equal rights and ownership of Menagerie. Some saw the gift of Menagerie as fair and just, while many others saw it as a slap in the face. Over time, it became apparent that Humans were adamant about having all Faunus live there. Such a confinement would also jeopardize the rights earned by Faunus in the Great War. In reaction to this, the Faunus fought back, sparking the Revolution. Historically-speaking, this war was fairly recent, but enough time has passed for Huntsman academy students to think of it as ancient history.
The war reached a turning point during its third year, in the Battle of Fort Castle where General Lagune, an inexperienced leader in the Human army, attempted to ambush Faunus troops in their sleep. The Faunus used their near-perfect night-vision to their advantage and defeated the Humans' larger army. It is unknown how much longer the war carried on after this.
In the aftermath of a war, likely the Revolution, the White Fang was founded for the purpose of acting as a symbol of peace and unity between Humans and Faunus. However, the Humans continued to discriminate against the Faunus, leading the White Fang to become a peaceful protest organization. Five years before the events of Volume 1, the White Fang's leader, Ghira Belladonna, stepped down and was replaced by Sienna Khan, who chose violent tactics over peaceful ones. The organization began carrying out terroristic acts such as setting fire to shops that refused to serve Faunus, hijacking cargo from companies that use Faunus labor, and in entanglements with the Schnee Dust Company, they also utilized murder and abduction. These tactics began bringing Faunus equal treatment, but out of fear, not respect.
Although the war was fought to prevent the forcible confinement of Faunus in Menagerie, the continent still boasts a large Faunus population. There are even Faunus who consider Menagerie to be a safe haven.