The Marine Corps was founded November 10, 1775 to serve as an infantry unit aboard naval vessels and was responsible for the
security of the ship and its crew by conducting offensive and
defensive combat during boarding actions and defending the
ship’s officers from mutiny. As of 2017, the USMC has around
182,000 active duty members and some 38,500 personnel in
reserve.

Semper fidelis ("always faithful")