They also tore down the park’s nearby monument to President Ulysses S. Grant.
Grant had led the Union Army during the Civil War, but married into a slave-holding family, and, briefly owned a slave for about a year before the war, according to the American Civil War Museum.
Key, who penned the lyric “O’er the land of the free,” had himself gone to court to defend the right to own slaves, according to The Smithsonian.
Roughly 400 protesters were in the park as the monuments were taken down and no arrests were made, according to the local NBC affiliate.
The statues are among many across the country dedicated to white men with ties to slavery or the Confederacy that have been targeted in recent weeks during the unrest over the Minneapolis police killing of George Floyd.
Shortly after protesters ripped down the San Fransisco monuments, protesters in Washington, D.C., toppled and torched the lone Confederate statue in the nation’s capital, of general Albert Pike.
In Richmond, Virginia, protesters have trained on the city’s assortment of confederate statues. Earlier this month demonstrators pulled down the monument to Jefferson Davis, the president of the Confederate States of America, that stood on along the city’s storied Monument Avenue.
The street’s most controversial Confederate statue, the massive monument to Gen. Robert E. Lee, has become a protest rallying point in the city. It’s also been heavily vandalized, with protesters also projecting Floyd’s face onto its pedestal.
Virginia Gov. Ralph Northam has announced he would be taking down the 60-foot-tall statue of Lee, only to be temporarily blocked by an ongoing court order.