Francis Scott Key was an American lawyer, author, and amateur poet who is best known for writing the lyrics to the United States' national anthem, "The Star-Spangled Banner." Key was born on August 1, 1779, in Frederick County, Maryland, and he grew up on a plantation near the town of Keymar. His family was deeply involved in the founding of the state of Maryland, and Key himself became a prominent figure in the legal and political communities.

Key attended St. John's College in Annapolis, Maryland, and later studied law in Virginia. He began practicing law in Maryland in 1801, and quickly gained a reputation as a skilled and persuasive lawyer. Key also became involved in politics, serving as a delegate to the Maryland state legislature and as a district attorney for the city of Washington, D.C.

Key's most famous moment, however, came during the War of 1812. In 1814, Key was sent by President James Madison to negotiate a prisoner exchange with the British, who had recently invaded Washington, D.C. Key successfully negotiated the release of an American physician who had been taken captive by the British, but he and his companions were not allowed to leave the British fleet until after the bombardment of Fort McHenry, a key defense of Baltimore, had ended.

As the battle raged on, Key watched from the deck of a British ship as the American flag continued to fly over the fort. Inspired by the sight, he began composing a poem that would later become "The Star-Spangled Banner." The poem was set to the tune of an old English drinking song, and it quickly became popular among Americans as a patriotic anthem. In 1931, President Herbert Hoover signed a law making "The Star-Spangled Banner" the official national anthem of the United States.

Key continued to practice law and write poetry after the war, but he never achieved the same level of fame as he did for "The Star-Spangled Banner." He died on January 11, 1843, at the age of 63.

In conclusion, Francis Scott Key was an important figure in American history who is best known for writing the lyrics to "The Star-Spangled Banner," the national anthem of the United States. His poem, which was inspired by the sight of the American flag flying over Fort McHenry during the War of 1812, quickly became a popular patriotic anthem and remains an important part of American culture to this day. Key's legacy as a writer, lawyer, and patriot continues to inspire Americans to this day.