The Marines Corps is a branch of the military service whose training prepares them to carry out integrated land, sea, and air operations. The first marines were commissioned during the American Revolution, only to be inactivated after the war. Congress permanently reestablished the Marine Corps in July, 1798. Legendary for their toughness, rigid codes of behavior, and adaptability, they have played an important role in almost every major war and conflict of the 19th and 20th centuries.