A ship covered with iron plates and used in the Civil War, in the famous Merrimack vs. Monitor ever naval battles between the ironclads in1862. They revolutionized naval warfare.
Military leadership in order of importance and decision-making responsibilities usually prioritized form the Commander-in-Chief (president), General of the Army, Lt. General, Major General, Brigadier General, Colonel, Major, Captain, Lieutenant, 1st Sergeant, Corporal Private