Exactly 230 years ago today, American General Benjamin Lincoln surrendered his force of 6,000 men in Charleston.

His move capped a 42-day British siege that had turned the central peninsula into a vast battleground.

The siege's end ranked among the Patriots' worst defeats in the Revolutionary War, and it all unfolded in and around what's now known as Marion Square.

At noon today, a group of historians and other onlookers will gather in the square, near King Street, to unveil a new historical marker highlighting this under-appreciated chapter in the city's history.

Mark Maloy, 25, a local history buff and National Park Service intern at Fort Sumter National Monument, helped pull it off, with help from the S.C. Societies of the Daughters of the American Revolution and Sons of the American Revolution, and the Maj. Gen. William Moultrie Chapter, Sons of the American Revolution.

"That area right in front of Marion Square was essentially like a World War I battlefield with a system of trenches and bombs exploding," he said. "Two hundred and thirty years later nobody realizes what happened right underneath their feet."

Gen. Charles Lord Cornwallis took the city and held it for more than two years.

While the Siege of Charleston ranks up there with the most significant Revolutionary War encounters in the state, there's little or no public interpretation. The new marker will stand near a tabby remnant of the city's colonial fortifications, but neither that remnant nor another nearby marker do much to explain the major battle.

Almost 100 patriots were killed during the siege, while 140 were wounded. British troops had 76 killed and 189 wounded.

"This was a very terrible defeat for the United States of America, but this is the first step in the path to Yorktown," where Cornwallis surrendered to end the war, Maloy said. "It was because of this that the state of South Carolina erupted into a civil war that the British couldn't control."

"South Carolina has the history," he added. "It's just a matter of bringing it to light."

The marker

THE SIEGE OF CHARLESTON, 1780

The British capture of Charleston in May 1780 was one of the worst American defeats of the Revolution. On March 30-31 Gen. Sir Henry Clinton's British, Hessian, and Loyalist force crossed the Ashley River north of Charleston. On April 1 Clinton advanced on the American defenses near this site, held by Gen. Benjamin Lincoln's Continentals and militia. The 42-day siege would be the longest of the war.

As Gen. Charles Lord Cornwallis closed off escape routes on the Cooper River, Clinton advanced his siege lines and bombarded Charleston. On May 12, 1780, in front of the American works near this spot, Lincoln surrendered the city and his force of 6,000 men, after what one British officer called "a gallant defense." The British occupied Charleston for more than 2 1/2 years, evacuating Dec. 14, 1782.

Erected by the South Carolina Societies of the Daughters of the American Revolution and Sons of the American Revolution, and the Maj. Gen. William Moultrie Chapter, Sons of the American Revolution, 2010