Commodore was a term that referred to two independent UNSC ranks: Commodore (standard) and Commodore Admiral. These ranks were reinstated in the 2550's as a result of numerous reformations following the Human-Covenant War and Civil War of 2553. The lesser of the two (Commodore) was a supplementary rank while Commodore Admiral replaced Rear Admiral, Lower Half. In informal situations, either of the ranks may be referred to as Commodore.