When did francis scott key write the poem that became the national anthem?
the morning after the battle of york, july 4, 1815
july 4, 1814
the night before the battle of fort mchenry, september 14, 1814
the morning after the battle of fort mchenry, september 14, 1814

Step-by-step explanation:

He wrote it the morning after the battle of Fort McHenry, September 14, 1814

The poem was originally called " The Defence of Fort McHenry " and he wrote it after he saw Fort McHenry being bombed. The morning after the battle, he was inspired by the sight of a lone U.S. flag still flying over the fort at daybreak.