being appointed to a brevet rank to temporarily serve in positions designated for higher-ranked officers (i.e., in lieu of promotion to permanent rank), officers might be awarded brevet rank as recognition for gallantry or meritorious service. American Civil War During the American Civil War, almost all senior Union officers received some form of brevet award, mainly during the final months of the war. But these awards were made for gallantry or meritorious service, rather than for command. In addition to the authorization in a previous law for awards of brevet ranks to Regular Army officers, an act of Congress of March 3, 1863, authorized the award of brevet rank to officers of the United States Volunteers. Thus, brevet awards became increasingly common later in the war. Some officers even received more than one award. Because of the existence of both Regular Army and United States Volunteers ranks, and the possibility that an officer could hold actual and brevet ranks in both services, some general and other officers could hold as many as four different ranks simultaneously. For example, by the end of the war, Ranald S. Mackenzie was a brevet major general of volunteers, an actual, full-rank brigadier general of volunteers, a brevet brigadier general in the United States Regular Army, and an actual Regular Army captain. Brevet rank in the Union Army, whether in the Regular Army or the United States Volunteers, during and at the conclusion of the American Civil War, may be regarded as an honorary title which conferred none of the authority, precedence, nor pay of real or full rank. The vast majority of the Union Army brevet ranks were awarded posthumously or on or as of March 13, 1865, as the war was coming to a close. U.S. Army regulations concerning brevet rank provided that brevet rank could be claimed "in courts-martial and on detachments, when composed of different corps" and when the officer served with provisional formations made up of different regiments or companies, or "on other occasions". These regulations were vague enough to support the positions of some brevet generals who caused controversies by claiming supposed priorities or privileges of brevet ranks that had been awarded to them at earlier dates during the war. Some full-rank brigadier generals in the United States Volunteers (USV) in the American Civil War had been awarded brevet brigadier general rank in the USV before receiving full-rank promotions