The Rectification War was an armed conflict between the forces of the Abbey of the Everyman and followers of the Outsider and other religious denominations between 1705-1708. It ended with the Siege of White Cliff, and the "purging" of those antithesis to the designs of the Abbey.
The War (1705-1708)
As tensions between the Abbey of the Everyman and adherents to the mysterious figure known as the Outsider grew, High Overseer John Clavering would construct the Abbey within the capital city of Dunwall in 1701 in an attempt to cement the Abbey's prominence within the Empire of the Isles. The Rectification War would promptly be declared in 1705, and would later be described as a "large, unifying conflict" against differing religions of the Isles. It ultimately ended with the Siege of White Cliff on the isle of Gristol in 1708.
In antiquity, the city of Whitecliff was home to "heretics" and worshipers of the Outsider. Following the Siege of White Cliff, a month of ceremonial rites and speeches by various Overseers would be copied down and transcribed, forming the Abbey's religious text, the Litany on the White Cliff. The war would see the transformation of the city from a once heretical outpost into a stronghold for the victors, and eventually a pilgrimage site for the faithful. It would also become the point from where all future Overseers would be chosen.
By war's end, the Abbey emerged as the prominent religious force within the Isles, and would be declared the official state religion of the Empire in 1711, under the reign of Emperor Yefim Olaskir.