How many years did Archibald Henderson serve as Commandant of the Marine Corps?

Archibald Henderson served as Commandant of the Marine Corps for an impressive total of 39 years, from 1820 to 1859. His lengthy tenure is significant in the history of the Corps, as he is often referred to as the "Grand Old Man of the Marine Corps." During his time in office, Henderson was instrumental in expanding and modernizing the Marine Corps, establishing its role and reputation as a versatile and capable military force. He oversaw significant developments, including the establishment of the Marine Corps School, improvements in the Corps’ organization, and participation in various military operations, which solidified the foundation for its future growth and capabilities. This duration of service is unparalleled in the history of the Marine Corps, further highlighting the impact he had during this pivotal period.