Francis Scott Key sailed out to free a prisoner, not to write a poem; twenty-five hours later, having watched the British shell Fort McHenry from a boat he could not leave, he saw a flag at dawn on September 14, 1814, and started writing anyway.

Francis Scott Key did not set out to write a national anthem. He set out to free a doctor.

Who was Key trying to save?

In August 1814, British troops burned Washington and turned north toward Baltimore. Somewhere in the chaos, soldiers arrested William Beanes, an elderly physician from Upper Marlboro who had, by most accounts, ordered a few British stragglers rounded up after the retreat. Key, a Georgetown lawyer with a talent for negotiation, agreed to go get him back. He sailed down the Chesapeake with John Stuart Skinner, the government's official agent for prisoner exchanges, carrying letters from wounded British soldiers as proof of good faith.

They found the fleet off the Patuxent River and were rowed out to Vice Admiral Alexander Cochrane's flagship, the 80-gun HMS Tonnant. Cochrane agreed to release Beanes. He would not, however, let any of the three Americans leave: they had spent days moving among British officers, seen the size of the force massing for Baltimore, and overheard enough of the attack plan that the admiral wasn't about to hand them back to shore.

A ringside seat to a bombardment

Key, Skinner and Beanes were shuffled from the Tonnant to another warship, HMS Surprise, and finally back aboard their own small vessel, still under guard. Historians have never pinned down that ship's name with certainty; contemporary letters mention only "the truce boat." It was tethered behind the British line, roughly six to eight miles from Fort McHenry, close enough to watch and far too far to do anything about what came next.

At first light on September 13, Cochrane's bomb vessels and rocket ships opened up on the fort guarding Baltimore's harbor. The bombardment ran for about twenty-five hours through driving rain and thunder, an estimated 1,500 to 1,800 rounds fired at a garrison that could barely shoot back (most British ships stayed well beyond the range of Fort McHenry's own guns). Major George Armistead's men held their positions through the night regardless, and by dawn the attack had clearly failed to force the harbor.

What flag was he watching for?

A year earlier, Armistead had ordered something specific from a Baltimore flag maker: a garrison flag so large the British would be able to see it "from a great distance." Mary Pickersgill, a 37-year-old widow who ran the family flag business, took the commission and put together a team — her 13-year-old daughter Caroline, her nieces Eliza and Margaret Young, and Grace Wisher, a 13-year-old Black indentured apprentice living in the household. Working with more than 400 yards of English wool bunting, occasionally spreading the fabric across the floor of a nearby brewery because the flag was too big for Pickersgill's own house, the group finished two flags on August 19, 1813: the 30-by-42-foot garrison flag and a smaller, sturdier storm flag measuring 17 by 25 feet. Both carried fifteen stars and fifteen stripes, one for each state then in the Union.

Which flag did Key actually see?

Here the popular version of the story gets ahead of the record. Rain and wind through the night of September 13 made the huge garrison flag impractical, so the fort flew its smaller storm flag for the entire bombardment; the version now enshrined in the Smithsonian never took a single hit from British guns. Only after Cochrane's ships disengaged on the morning of September 14 did Armistead's men lower the tattered storm flag and run up the giant one, partly as a show of defiance for anyone still watching from the water. Whether Key could tell one flag from the other at that distance is unrecorded. What he wrote down was simpler: after a night lit only by rockets and shell bursts, dawn showed him a flag, and the fort had held.

Four verses on the back of a letter

Key began writing almost immediately. He is said to have scratched the opening lines on the back of a letter he happened to be carrying in his pocket, working out the meter of a song he already had in his head. Once the British let the truce boat go, he finished a draft in a Baltimore hotel room over the following two or three days, then had it printed as a handbill titled "Defence of Fort M'Henry." The Baltimore Patriot ran the full text on September 20, 1814, a week after the bombardment ended.

Key set his words to a tune already familiar in American taverns: "To Anacreon in Heaven," composed decades earlier by John Stafford Smith for a London gentlemen's music club, of all things a drinking song. The pairing stuck. Sheet music soon carried the new title "The Star-Spangled Banner," and the Navy adopted it for ceremonial use by the 1890s.

From handbill to national anthem

Congress took much longer to catch up. For more than a century, "The Star-Spangled Banner" competed with "America the Beautiful," "Hail, Columbia" and "My Country, 'Tis of Thee" for the unofficial title, and critics openly complained that Smith's tune spanned an octave and a half, too wide a range for most people to sing comfortably. Veterans' groups lobbied Congress for decades before lawmakers acted. President Herbert Hoover signed the bill making it the official national anthem on March 3, 1931, a hundred and seventeen years after Key wrote it on the back of that letter.

The flag today

The garrison flag survived Key by more than a century, passed down through Armistead's family, lent out for parades and souvenir-snipping until visible chunks of it were missing, and loaned to the Smithsonian in 1907; Armistead's grandson made the gift permanent in 1912. Conservators there have spent years since stabilizing what's left, and the flag now hangs in a dim, climate-controlled gallery at the National Museum of American History, tilted at the same 10-degree angle it once flew at over the ramparts. Millions of visitors walk past it every year, most of them able to hum the tune without ever having heard the story of the lawyer who wrote the words from a boat he wasn't allowed to leave.

The anthem it inspired still opens ballgames and graduations, sung by crowds who mostly know four lines and hum the rest. Key wrote only what he could see through smoke at daybreak, not knowing anyone would still be singing it two centuries on.

Sources

• Smithsonian National Museum of American History, "A Moment of Triumph" (amhistory.si.edu)
• National Park Service, Fort McHenry National Monument and Historic Shrine, "The Star-Spangled Banner"
• National Park Service, Fort McHenry National Monument and Historic Shrine, "The Great Garrison Flag"
• American Battlefield Trust, "Short History of The Star Spangled Banner"
• American Battlefield Trust, "The Star-Spangled Garrison Banner"