BALTIMORE, Md. (WHTM) — By 1814, the War of 1812 was not going well for the United States. Sometimes battles were won; sometimes they were lost. But for the first two years of the war, the British were not giving it their full attention. They were much more concerned about the doings of Emperor Napoleon Bonaparte on the European continent.

Then, in April of 1814, Napoleon was forced to abdicate and was exiled to the island of Elba off the coast of Tuscany, Italy. Suddenly Britain had about 14,000 troops available to deal with those upstart Americans. On August 14 General Robert Ross arrived at the Chesapeake Bay with 4500 battle-hardened soldiers. (Ironically, peace negotiations between Britain and the U.S. started on August 8, but the British meant to keep the pressure on.)

On August 24, at the Battle of Bladensburg, the British troops crushed a poorly placed and poorly led American force, in what’s been called “the greatest disgrace ever dealt to American arms”. The British then marched unopposed into Washington and burned many government buildings, including the White House and Capitol.

On August 27 The British sailed up the Potomac and occupied Alexandria, Virginia for over a week, gathering supplies.

Then they turned their attention to Baltimore. The British fleet sailed up the Chesapeake to the mouth of the Patapsco River. On Sept. 12, British troops disembarked at North Point to begin an 11-mile march, to attack the city from the east. Things started to go wrong for them. Their commander, General Ross, was killed in a skirmish. Then they ran up against a force of 3000 Maryland Militia. The Battle of North Point, as it’s called, was no Bladensburg. The Marylanders held off the British for almost an hour before retreating in good order. Technically the British won the battle but suffered heavy casualties in the process.

The British would not resume their advance until the 13th, only to stop just outside Baltimore when they found their way blocked by an earthwork over a mile long, which the defenders of the city had been preparing for over a year. Manning the fortifications, 15,000 Americans-many eager to avenge Bladensburg.

To overcome this barrier, the soldiers would need the help of the British warships, and to sail further up the Patapsco River to help, the warships would first have to subdue the fort protecting the entrance to Baltimore’s Inner Harbor-Fort McHenry.

The British Navy began a bombardment of the fort which went on for over 27 hours. Through heavy rain, the ships showered the fort with over 1500 cannonballs, exploding mortar shells, and a new invention, the Congreve rocket.

During the 13th, and on through the night, the flag flying over the fort was a “storm flag” meant to be flown during bad weather.

Early on the morning of September 14, the storm flag was hauled down. Then a different flag was raised.

When he took command of Fort McHenry the year before, Major George Armistead wanted “to have a flag so large that the British will have no difficulty in seeing it from a distance.” Baltimore flagmaker Mary Pickersgill delivered.

Original Star Spangled Banner, on display at Museum of American History (Smithsonian)

The flag raised on the morning of September 14th was a “garrison flag”, an extra-large flag flown on Sundays, holidays, and special occasions. The Fort McHenry flag was huge even by garrison flag standards. It measured 42 feet by 30 feet. Each stripe (fifteen of them, one for each state in the union) was two feet wide, as were the stars from point to point. If the British hadn’t known their assault had failed before, they certainly knew it after the flag went up.

Certainly Francis Scott Key understood. He had sailed out to the British fleet to negotiate the release of a prisoner, then was held by them until after the attack was over. When he saw the big garrison flag raised, he was moved to write a song about it. Both the song and the flag became known as the “Star Spangled Banner”. The song became our national anthem, and the flag, carefully conserved, is on permanent exhibit at the Smithsonian Museum of American History.

By a 1948 proclamation by President Harry Truman, a flag always flies over Fort McHenry. They have a number of flags of different sizes, for use in different types of weather. But when the weather allows, the flag over the fort is a full-sized replica of the original star spangled banner.