Final answer:
Francis Scott Key composed 'The Star-Spangled Banner,' inspired by the American flag's endurance after Fort McHenry was bombed in the War of 1812.
Step-by-step explanation:
The main idea of the paragraph is that Francis Scott Key wrote what would become the U.S. national anthem, "The Star-Spangled Banner," inspired by the sight of the American flag still flying after the bombing of Fort McHenry during the War of 1812. This poem, originally titled "In Defense of Fort McHenry," was composed after he witnessed the flag's persistence despite a severe twenty-five-hour bombardment by the British forces. Key's words reflect the resilience and endurance of the American spirit in the face of adversity.