Defenders Day is observed in Baltimore and the entire state of Maryland on September 12, commemorating the successful defense of Baltimore from the British Army during the War of 1812. This conflict, which lasted from 1812 to 1815, is significant in U.S. history as it reinforced the country's status as a sovereign state. The day marks the British attack on Fort McHenry, which took place on September 13, 1814, after their advance on Baltimore. The defense inspired Francis Scott Key to write the poem "Defense of Fort McHenry," which later became "The Star-Spangled Banner," the national anthem of the United States. The holiday serves as a reminder of this pivotal moment in American history and is recognized as a legal holiday in Maryland.