"The Star-Spangled Banner" is the national anthem of the United States of America. The lyrics come from "Defence of Fort M'Henry", a poem written on September 13, 1814 by the 35-year-old lawyer and amateur poet Francis Scott Key after witnessing the bombardment of Fort McHenry by British ships of the Royal Navy in Baltimore Harbor during the Battle of Fort McHenry in the War of 1812. Key was inspired by the large American flag, the Star-Spangled Banner, flying triumphantly above the fort during the American victory.
The poem was set to the tune of a popular British song written by John Stafford Smith for the Anacreontic Society, a men's social club in London. "To Anacreon in Heaven" (or "The Anacreontic Song"), with various lyrics, was already popular in the United States. Set to Key's poem and renamed "The Star-Spangled Banner", it soon became a well-known American patriotic song. With a range of one octave and one fifth (a semitone more than an octave and a half), it is known for being difficult to sing. Although the poem has four stanzas, only the first is commonly sung today.