BALTIMORE — This week marks the 200th anniversary of “The Star-Spangled Banner,” and Baltimore is pulling out all the stops: massive fireworks displays, historical re-enactments and live performances all over the city’s Inner Harbor. But what does the Star-Spangled Banner’s birthday have to do with Baltimore? Most people have no idea, and the answer is a whole lot. Here are things to know about America’s national anthem and its birthplace:

Why does the national anthem have to do with Baltimore?

Pretty much everything. The War of 1812 — commemorated on the current Maryland license plate — was in large part defined by the Battle of Baltimore in September 1814. This pivotal battle marked a turning point in the United States’ 2½-year war with the United Kingdom, with America repulsing British forces despite the heavy bombardment of Fort McHenry. U.S. commander George Armistead refused to surrender and at the end of the assault, British troops retreated and American troops raised the American flag.

Shortly before the attack began, the United States sent an enterprising young attorney (and amateur poet) named Francis Scott Key to negotiate the release of American hostages on British naval ships. The British agreed to release the hostages, but Key and the others had to wait until after the bombing of Fort McHenry to return to shore. When the smoke from the bombs cleared, Key saw the stars and stripes of the garrison flag. Right there, on Sept. 14, 1814, he wrote the verses of “The Star-Spangled Banner.” It was soon put to music, the tune borrowed from a British anthem.

Shakespearean roots, lasting legacy

Although the phrase “Star-Spangled” was made famous through Key’s text, historian Marc Ferris, author of “Star-Spangled Banner: The Unlikely Story of America’s National Anthem” said first references in literature were made much earlier: William Shakespeare twice used the turn of phrase, once in “A Midsummer Night’s Dream” (“by spangled star-light sheen”) and again in “The Taming of the Shrew” (“what stars do spangle heaven with such beauty”).

But Key did coin one phrase that gave way to a motto so ubiquitous that it appears today on American currency, Ferris said: “In God We Trust” was inspired by a line in “The Star-Spangled Banner’s” fourth verse: “Then conquer we must, when our cause it is just, And this be our motto: In God is our trust.”’

Francis Scott out-of-key

“The Star-Spangled Banner” is one of the nation’s best-known and most beloved songs, belted out with more frequency and greater gusto than any other in American history except, maybe, “Happy Birthday.” But Key, the wordsmith behind the anthem’s lyrics, was only an amateur bard. He’d never written a song, and there’s a good reason, according to historian Marc Leepson, who published the first modern biography of Key, “What So Proudly We Hailed.”

“He was an amateur poet, but not just any poet — he was a bad amateur poet,” Leepson said. “And he never wrote a song in his life. Why? His family described him as ‘unmusical.’ But that probably means tone deaf.”

How embarrassing

Key owned slaves, and his descendants were supporters of the Confederacy. But during the Civil War, 18 years after Key died, Northern soldiers adopted “The Star-Spangled Banner” as their unofficial national anthem. Meanwhile, Confederate soldiers adopted the tune “Dixie,” written by Daniel Decatur Emmett — a northerner.

“It’s the greatest irony in American history,” Ferris said, adding that Key’s family members later denounced the “Star-Spangled Banner.”