During the American Civil War, the Confederates attacked Fort Stevens in July1864. Lincoln journeyed to the front to inspect Union defences. The task of showing him around fell to young Oliver Holmes, aide to the commanding general.
When Holmes pointed out the enemy in the distance, Lincoln, with his high plug hat, stood up to look. A snarl of musketry fire came from the enemy trenches. Grabbing the president by the arm, Holmes dragged him under cover, shouting, "Get down, you fool!" When he realised what he had said, he was sure that disciplinary action would be taken. But to his great relief, Lincoln said to him in an amused tone just before leaving, "Goodbye, Captain Holmes. I'm glad to see you know how to speak to a civilian."