O see the poem that became our national anthem

-USA Today

Eighty years ago this week, President Herbert Hoover signed a resolution establishing an American anthem: Francis Scott Key's Star-Spangled Banner.

On Tuesday, in preparation for its anniversary celebration, Key's original handwritten poem left the Maryland Historical Society — its home since 1953.

The paper, suspended in argon gas in a specially designed case, traveled in a Dunbar Armored car with an escort of police and dignitaries to the state Capitol building in Annapolis.

To avoid damage caused by sunlight, the document is displayed for only 10 minutes each hour.

On Wednesday, the 80th anniversary of the law, it will go on display to the public for three months at Fort McHenry, the site of the ferocious battle that inspired his depiction of "the rocket's red glare, the bombs bursting in air."

Key wrote the iconic words 197 years ago in a Baltimore tavern. The country was in its second year of war with the British, and Key had just witnessed the War of 1812's Battle of Baltimore on Sept. 13 and 14, 1814.

He crammed four verses onto a piece of paper smaller than a school notebook.

"It represents the spirit of America," says Burton Kummerow, president of the Maryland Historical Society in Baltimore. "To have the document around is really a remarkable thing. It's part of the fabric of America."

Key, an attorney, had been sent to meet with British officers on their ships in the Chesapeake Bay to negotiate the release of William Beanes, a physician from Upper Marlboro, Md., as part of a prisoner exchange. He dined with the British officers, who eventually agreed to the exchange.

But Key and his companions had spent enough time on the ship that they were now aware of the British plans to attack Baltimore, and they had seen the strength of the British fleet.

The British held Beanes, Key and other Americans on the ship so they couldn't divulge the attack plans.

Key watched from his vantage point in the bay as 50 British warships shelled Fort McHenry for 25 hours, firing nearly 1,800 bombs and rockets, Kummerow says. American soldiers repelled the land and sea attacks. The British retreated.

When the smoke cleared, Key could see the American flag still aloft over Fort McHenry. "He was really taken when he saw the flag was still flying," Kummerow says. "It was one of those incredible, magnetic moments."

Key wrote the poem that became The Star-Spangled Banner the night he was released, Kummerow says.

"He obviously had it well in mind," Kummerow says, noting the original sheet of paper has just two cross-outs.

It was published in several local papers as The Defence of Fort McHenry and became popular. It was set to music written in the 1770s.

"Francis Scott Key knew about the song. He probably had the song in mind when he wrote it," Kummerow says.

The Maryland Historical Society also owns the original sheet music.

"When Francis Scott Key wrote this song and the flag became a great symbol, it really launched that feeling of patriotism in the country," he says.

It caught on as a patriotic song by the Civil War, but it wasn't until March 3, 1931, that Hoover signed the law that made The Star-Spangled Banner the national anthem. Kummerow marvels, "It took more than 100 years."

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