THE BREVET RANK
The innovation of the brevet rank was adopted subsequent to the War of 1812. It was to be awarded to officers who had distinguished themselves in action or had served ten years in grade. Such commissions in the Marine Corps, date from April 16, 1814. In essence, this amounted to an honorary promotion, w/o any increase in either pay or seniority.
Navy Regulations did not permit the award of a Medal of Honor to an officer before 1916, therefore, it was common practice in the Marine Corps for an officer to be awarded a brevet in lieu of a Medal of Honor.
THE BREVET MEDAL
In 1921, CMC John A. Lejeune proposed that surviving officers who held brevets be given a special decoration. This was approved, and all living brevet holders were awarded the Brevet Medal, which resembled the 1917 version of the Navy Medal of Honor, a gold cross pattee, with a red ribbon seasoned with gold stars. The Brevet Medal was second only to the Medal of Honor in precedence.
Re Marine Corps Book of Lists, Nofi, Combined Publishing, 1997