A ship covered with iron plates and used in the Civil War, in the famous Merrimac vs. Monitor first ever naval battles between the ironclad in 1862. They revolutionized naval warfare.
Military leadership in order of importance and decision-making responsibilities usually prioritized from Commander-in-Chief (president), General of the Army, Lt. General, Major General, Brigadier General, Colonel, Major, Captain, Lieutenant, 1st Sergeant, Corporal, Private.